Infrared Paint Remover: V2

By Dave
Category: Tools
Time Required: 3 hours
Difficulty: Moderate

A modern method of removing paint from wooden surfaces is the use of infrared rays. This method has gained popularity over the past decade as an alternative to mechanical and chemical methods of removing paint. Mechanical methods such as sanding, grinding, or shaving usually increase hazards such as lead dust. Chemical solutions minimize the lead dust but result in a gooey mess that requires cleanup and more chemicals for neutralization. Infrared paint removers ofter an alternative which minimizes dust and eliminates chemicals. When exposing a painted surface to infrared rays, the rays penetrate the paint, warm the substrate below the paint, thus releasing the paint’s grip. In practice, the infrared paint remover (IPR) held over a painted spot will cause the paint to slowly bubble and lift, making it easy to scrape it off with a scraper. IPRs are seen most often used by people restoring old houses or windows. They are, however, increasingly seen used in a variety of applications. The disadvantage of an IPR is that it is not guaranteed to be effective in every situation. See the conclusion of this article for more detail. IPRs are most effective on thick layers of old paint, especially aligatored paint. They do not work well on calcimine, milk paints, and will not remove shellac or varnish.

Note that IPRs are not the same as "hot plates," which heat paint via convection. Hot plates scorch and boil the paint through proximity to a heated element. That method risks scorching the wood substrate and releasing toxic gases. IPRs rely not on convection, but mostly on radiation. The goal is to penetrate paint and warm the substrate (wood), releasing the bond between paint and wood, slowly, without raising the temperature high enough to vaporize lead. When you stand at a sunny window on a cold winter day, and you feel the sun’s heat on your face even though the air outside may be zero degrees, you are being heated by radiation. In such case, energy is transferred directly to you and not via physical contact with an warmer object (conduction), nor using air as a carrier of heat (convection).

In August of 2004, frustrated at the high cost of commercial Infrared Paint Removers ("IPRs"), I cobbled together a home-made unit using a quartz heater and some miscellaneous hardware. I wrote up a small page outlining my experiments for the benefit of other old house restorers out there. The response was unexpected. It seems there are many out there like to tinker, save $, and DIY.

Here now is Version 2 of the IPR. Having traded my original scratch-built quartz unit for a Herbeau fireclay sink, and in need of an IPR, I elected to investigate this new and promising modality of paint removal: ceramic infrared.

Theory:

Commercially sold IPRs use quartz rods to generate infrared rays. My unit would be based on a ceramic emitter instead. Why ceramic? One reason is that a ceramic unit would be easier to build with fewer parts. Commercial ceramic emitters are readily available. Efficiencies for ceramic emitters run from 85 to 96% whereas quartz ran around 60%. Therefore, a higher percentage of the energy supplied to the unit would be transmitted as infrared rather than light. Quartz rods tend to have infrared hotspots. Cermaic on the other hand, produces a more evenly distributed heat.

The Unit:

Anyway, yet again, this is the time to point out some safety issues and make a disclaimer. Making your own IPR involves electricity. The project involves wiring as well as drilling, sanding, and cutting. (jeez doesn’t sound too bad) I am not advocating that you run out and build one, I am presenting my method here for your review. If you do make one, you do so of your own accord. If you electrocute yourself, or burn your house down, well, hey, that’s life, and your own responsibility. I am comfortable with the potential hazards. You may not be, and I urge that if you should make one anyway, you proceed with safety in mind and a good dose of common sense.

Thus my intention to build a new, ceramic based, IPR for the same or less money.

Steps

Step #1:

The first step was to order the ceramic emitter and gather some of the other parts that would be required to get this show on the road. The emitter I selected was a Salamander FTE module. This particular model (FTE-120-1000) is specified to operate at 120 volts. The emitter is manufactured by Mor Electric and can be purchased on their website.

Conclusion

The ceramic element requires about ten minutes to heat up. When fully heated, the red logo on the element turns black. This unit throws off some serious infrared radiation. Paint sees this thing coming and jumps off the wood in fear. I will add action photos soon.

Caution: the housing gets too hot to touch. Do not touch it when operating the IPR.

There some improvements to be made and concerns about the design. These are things I am working on:

1. The unit gets very hot, and while I have no concerns about the housing and element, I am concerned about the cord wiring. This is why, as I mentioned above, I intend to sheath the cord wires in Teflon tubing. Inspection of the unit after operation has not shown any melted wire insulation, but hours on this IPR are still low. I do not know what the temperature rating of the extension cord wire is. More study required. Also, after each use, I open the cover and inspect the wires. If you make one of these, you should too.

2. The infrared output of this thing is phenomenal. The 1000-watt element I am using almost seems too much. The height adjusters could actually be longer than 7.5 inches. Using a variac, I will lower the operating power and see if performance suffers. I suspect I might go with a 750-watt element from the supplier rather than the 1000-watt I am using now.

Update: The 750W element works fine. I suggest for an all purpose unit, you use the 750W element.

3. The unit weighs 3 lbs. 8 oz. This is a little too much. A weight-loss reduction program might include replacing the steel end-plates with home-cut aluminum ones. A series of holes could also be drilled in the housing itself. Enough holes would lessen the weight and perhaps vent the heat better.

Use: These devices are mainly intended for restorers of old houses and others seeking to remove many layers of old paint from wood surfaces. The thicker and older the paint, the better it works. IPRs will not work as well on fresh paint. Hold the unit over a spot until the paint begins to bubble and lift. Do not leave long enough for the paint to scorch or smoke. You want the least time possible. When the paint has separated from the surface, scrape it off.

Time over spot and Height Adjuster length:

It's very difficult to assign a standard time/riser length to the IPR unit. The reason is that different paint sites require different lengths and/or time held over a spot. The factors that weigh into this are:

Age of the paint.
Composition of the paint.
Thickness of the paint.
Color of the paint (white reflects more energy back)
Type of wood underneath (density)
Moisture of wood underneath

All of the above, and maybe a few I've forgotten, affect the "personality" of the job. You'll find some paints lift very quickly at 7 inches, while others need closer spacing for the same time frame. You may find that some paints just don't lift at all (like calcimine and milk paints). The rule of thumb is to use the most distance that your patience can deal with. The slower you heat the paint, the more the chance the wood beneath has to absorb the heat and release. Also the longer you take (slower you heat), the less chance lead vapor releases, because the paint gets a chance to release before being heated too hot. Due to the differing nature of old paints, one of three things will always have to be variable: the power of the IPR, the length of the risers, or the time you hold it over a spot. I tend to vary the distance so that the job at hand takes about 20 - 30 seconds to bubble a good patch. I have taken to simply removing the risers and letting the nature of the job dictate where I hold the unit, but you can also have 2 or 3 sets of risers on hand. I'd say one set at 5" and one at 4". A three-inch set may be ok, but you want to be careful when you start getting that close. I have seen some paints that would catch fire before they let go; if you need to get 3" close, then the IPR might not be suited to the job. Of course, if you built your unit with only one job in mind, you can cut the risers to suit that job's needs. One of the benefits of a "top heavy" unit is that nobody can accidentally leave it unattended face-down while on, thus starting a fire. If your unit can sit happily, it is a good idea to make a metal "tray" for it to sit in, so as not to burn whatever you put it on. Even after powering it off, it needs a good 10 minutes before it can safely be aimed at something.

I hope you enjoyed my second experiment.

14 Responses to Infrared Paint Remover: V2

Dave on December 4th, 2012 at 5:51 am said:

Hi. Yes I wrote version 1 as well. That unit used quartz tubes. There are several concerns with what you propose. You can judge whether they are important to you. One is safety; if the unit stands by itself, you will most certainly be tempted to set it down. If you absentmindedly leave it sitting for more than 30 seconds or so you risk fire and/or scorching the wood. Even when turned off the unit needs minutes to cool to safe levels. A unit that cannot be left in a dangerous position wont be. Another concern is the legs , especially 4 points, scratching the wood. The legs get real hot, and it’s easy to make “snail tracks” or brandings in the wood if you’re not careful. I typically remove the risers altogether when working so that nothing touches the wood. Another concern is that you typically should use this device vertically rather than horizontally. When vertical the device absorbs far less of its own heat. I worry a bit about horizontal use for extended periods. Fortunately, unless you’re doing a floor, most work can be positioned vertical. Lastly you mentioned weight. Every ounce really does count when holding this thing vertically. If you can be mindful of these risks and warnings, then you can perhaps experiment with some trestle style legs. –Dave

Reply ↓
casey.gonzales1@gmail.com on February 22nd, 2013 at 7:18 am said:

Can you tell me how you built the infrared tool that you built first. I am interested in infrared not ceramic.
Thanks,

Reply ↓
MIchelle on March 17th, 2013 at 11:33 am said:

HI Dave — In case you check in, I would also love if you could post or PM the first set of instructions. I found and bookmarked them on the Ocean Manor page like about 2 years ago or something close. And I bought the stuff I need to make V1, incl the infrared heater (the ceramic is – I think – going to be too heavy for me to use effectively). Just never have had the time to put it together, but with spring approaching it is now a top priority to get my exterior painting done, and I have a garage covered with lead paint that I cannot get anyone to touch for a reasonable price. And now them website seems to be gone. Along with it, V.1 of the stripper. I recall that you discussed in pretty good detail how to deal with removing and re-seating and wiring the infrared tubes Sure could use that guidance again. If you get this, and can shoot me an e-mail, I’d be ever so grateful to you for your help. — Michelle mpaninop@gmail.com

Reply ↓
mpaninopoulos on March 17th, 2013 at 11:38 am said:

Oh look! Some amazing person made a pdf of your previous instruction and posted it. http://www.broadwaydistrict.org/paint%20Remover%20Instructions%201.pdf QUICK run to print it off before it ends up vanishing. And God Bless the Interwebz! And thanks again for working this all out and posting it for the rest of us. A great public service.

Reply ↓
Christine on April 4th, 2013 at 12:55 pm said:

Have you done any temperature testing of the hot paint? Is it over 1000 degrees F? Is it safe and doesn’t vaporize the lead in most pre-1978 paint? Would you tool pass any electrical safety testing? Beware.

Reply ↓
Andre on April 10th, 2013 at 11:11 pm said:

I think small piece of aerogel insulating blanket past reflector will protect aluminum body from heat. I know about IPR for a long time, however good it can be for a home owner, the liability starting a fire keeps me from using it. I worked on many old houses and sometimes siding insulation can be 100 y.o. dry hemp ropes , paper dry as gunpowder etc.
I will try to make IPR just to use on contured window frames/sash. For the siding, nothing works faster ( but requires skill) then Paintshaver. With powerful 2HP vacuum, Most of the residue is sucked into it . There are some tricks to make wood unclog after sanding , then
it is ready for primer. Either way sanding wood after removal is a must because it removes
all residue from top of the surface.

Reply ↓
Andre on April 10th, 2013 at 11:25 pm said:

OK I forgot to tell you folks that I saw some aerogel pieces on ebay…. It is not cheap though but the latest technology in insulation

Reply ↓
Andre on April 10th, 2013 at 11:27 pm said:

I also found those ceramic elements on ALIBABA and they are way cheaper there but unfortunately, sold in bulk…

Reply ↓
Andre on April 17th, 2013 at 9:53 pm said:

Hi there! I just received the body part and it seems that heat conducts through the body of the unit by the contact with the reflector. Two rows of assimetrical holes into the aluminum part that skirts the reflector will decrease surface of heat transfer from the reflector. There is a heat reducing channel on outside edge of the aluminum skirt but there is still significant contact with aluminum frame. Perhaps strip of silicon tape will help? Any ideas???
I also think that instead of aluminum tubes hiding the handle’s bolts rigid plastic tubes to be used further adding to insulation of handle from the body. Most of the weight comes from aluminum sliding lid part. But I would not drill any holes into those parts hence they isolate electric circuits. Also I would insert thin aluminum foil under the holes made in the skirt to prevent any posibility of moisture getting in there. Aerogel should arrive tomorrow and I am excited to finish the product coming weekend. Any ideas on thin insulating tape that resistant to high temps?
Regards
Andre

Reply ↓
Robert on April 30th, 2013 at 2:09 pm said:

My house was built in 1960 and is mostly brick with the exception of the trim work and wooden garage doors. The garage doors and all the trim around the garage doors are in especially ugly shape. The paint in these areas looks like alligator scales that are very thick and too hard to try and scrape. I ordered all of suggested parts for this Infrared Paint Remover V2 [went with the 1000 watt version] and I put everything together as outlined in the steps. I can say that the Infrared Paint Remover V2 does work because i was able to successfully heat and strip the paint on one of the vertical posts that surrounds the garage door. The post was successfully stripped of its alligator scales all the way down to the wood and then primed for paint. With that said, I must also say that the amount of time and effort it takes to do this is way beyond what I was hoping. It took me over six hours to do the one post that is roughly eight inches wide and eight feet tall. I received many eye rolls from my wife, but I was determined to have the new tool work. And although I can say that it did work, I must also say that I have admitted defeat and I will be replacing the garage doors and trim work that have these alligator scales with new trim pieces and new garage doors.

Reply ↓
Christine on May 23rd, 2013 at 9:03 am said:

Handy people: Yikes! You are taking risks with yourself, your homes, kids, and neighbors. Dave, why are you not warning them about high heat, wiring and wood fires, lead-paint toxicity, and other serious safety issues? You publish world-wide and have a disclaimer, but it’s scary that you encourage experiments with dangerous materials. I know I’m a skeptic and am discouraging good ole American ingenuity, but please folks know what your are messing with. Read up on lead-safe work practices at http://www.epa.gov/lead .

Reply ↓
mnphysicist on May 27th, 2013 at 10:46 pm said:

Christine, I’d be very leery of using surface temperature as a means of determining lead emissions or not when using radiant heat transfer. There are a multitude of ways to get errant surface temperature readings (more so with quartz tube emitters than ceramic) and there may be many other factors at play when it comes to lead emissions. One thing that’s interesting about this mod is its vertical orientation, in that it should generate a convective plume which would should keep the lead emissions further from the operator than its predecessor. Bottom line, It would be interesting to look at various paint profiles and related lead emissions for both quartz and ceramic infrared heating methods…. but I’m not quite sure how to take something like that on without significant lab gear.

Andre, Kapton tape is super thin and much more heat resistant than Silicon tape… but its so thin if might not be all that helpful for where you are trying to use it. What you might try is some silica mesh (McMaster sells it in small quantities), or if you have enough space some Kaowool.

Reply ↓
Bob W on June 5th, 2013 at 6:43 am said:

After looking into the brand-name IPR’s and both DIY ones, I am very glad to have gone the route of this particular version. Mor Electric typically has an expected lead time of 4- to 6-weeks on the parts purchase, but they were able to expedite my purchase once contacted. Still having concern for my knuckles (I’m pretty accident-prone), I fixed a flat trowel in place instead of the hardwood handle. This gave me a flat surface to lay the unit down, has had no heat transfer to the trowel plate, and the handle grip is molded for a hand. I’m also hoping the rectangular trowel will make mounting onto a stand more stable. Here is the unit:

It has performed very well so far, cleaning 3-4 layers of paint from my garage, though the clapboard cleans more easily than molding. Thanks for the great plans!

Reply ↓
- Bob W on June 5th, 2013 at 6:44 am said:
  
  Another attempt to post the image location…
  [IMG]http://i42.tinypic.com/2wgdnqp.jpg[/IMG]
  
  Reply ↓