TheSamba.com :: View topic - Removing paint with a propane torch and putty knife

Wed Nov 28, 2012 8:41 am

Back in 1988 I took a tour of the Harrah's restoration facility in Reno, NV. (They did outside restorations in addition to the ones for their museum.) I saw a worker there who was doing a private resto on a 356, and he was removing its paint by heating a small area with a propane torch until the paint blistered, and then scraping it off with a putty knife. It seemed to be a pretty good way of removing paint, but I've never seen anybody do it since then. Is this an OK method of removing paint from a 356?

Wed Nov 28, 2012 9:07 am

Bill
I have not tried the torch method, but have used a heat gun. Generates lots of fumes and will remove bondo but save lead(if you don't get it too hot). Easier cleanup than chemical paint removers.

Wed Nov 28, 2012 9:59 am

I've done it. It has it's own set of problems. The fumes are bad, you do have to worry about what's behind whatever you're stripping if you don't want to start a fire, and if there's undercoating the fumes and the fire danger are even worse.

You're going to have to use chemical stripper eventually to get all the grunge off and get into the tough spots, and while I can't prove this, it always seemed to me like the remaining paint was 10X harder to remove with the stripper after it had been melted with the torch. In my opinion, most of what you gain in time using a torch you give right back when you're trying to do the final clean-up.

Wed Nov 28, 2012 10:39 am

Check out this thread

http://www.thesamba.com/vw/forum/viewtopic.php?t=76072&highlight=oven+cleaner

Wed Nov 28, 2012 12:39 pm

Having removed paint more times then I care to remember, I use a torch to remove bondo and use chem strippers, the harsher the better, to strip paint. It really is not that messy if done right and you used tarps or paper to collect the mess. It also causes no damage to the metal unlike media blasting or heat and no dust all over creation like when you use a DA. It produces noxious fumes so ventilate well and wear a 3M mask.

Wed Nov 28, 2012 8:17 pm

OK, at my shop we often use an "all of the above" approach. The first step is a coarse abrasive on a DA around where obvious rust has exposed itself. The trim the area out that will be replaced. Why waste time on an area to be replaced or pay a blaster to do that eventually?
Chemical stripper is good on certain coatings, mainly enamels, always scratched to promote chemical penetration. We use it on big areas for avoiding the aforementioned warping issues when appropriate.
Old undercoating is primarily removed with a special wire wheel that "claws" the muck off quickly. Some undercoatings need to be torched/charred, especially in corners. Then, media blasting (often sand on a 'hard case') where the rust and nooks and crannies can be addressed, staying away from big low-crown areas. When debris removal and neutralizing is complete, epoxy "shop coat" primer is applied, usually on a rotisserie so gravity lets the waterproof coating seep into seams otherwise difficult to saturate. This, of course, is on a totally bare 356 shell, but methods may be scaled down for a smaller approach. As posted, be aware of the mess, fumes, and personal exposure.

Wed Nov 28, 2012 9:15 pm

Given all the proper cautions and disclaimers, my personal experience (surely less than many) is that heat and a scraper is definitely the best way to deal with bondo.... especially if its thick.

Thu Dec 06, 2012 1:21 pm

i used a hot air gun, and a scraper this removed every thing with ease it really did but it has left some scratches in the body. But it's better than 4 different colour changes on the car :wink: it did use to look like an over weight bondo filled 356 but in real terms it's a solid body so I don't get the whole bondo for no reason on my car it's light now!
:lol:

Thu Dec 06, 2012 6:04 pm

Kind of getting away from the propane torch/scraper question, but a few years back I learned a trick withchemical strippers that I think is worth sharing (although maybe everyone else already knew this and it was just me who didn't).

Buy a couple of rolls of cheap saran wrap along with your gallon of stripper. Brush the stripper on nice and thick. Then cover the whole area with strips of saran wrap. Come back many hours, or even days later. Lift the saran wrap and most, if not all, of the paint/primer (even some bondo) comes up with it. If the timing is right, it sorts of bonds to the saran wrap instead of the car. The saran wrap holds the chemicals down in the paint where they can work, instead of evaporating. Fumes are cut by probably 95% or better.

Works for me anyway.
DG

Fri Dec 07, 2012 12:54 pm

dg58innm wrote: Kind of getting away from the propane torch/scraper question, but a few years back I learned a trick withchemical strippers that I think is worth sharing (although maybe everyone else already knew this and it was just me who didn't).

Buy a couple of rolls of cheap saran wrap along with your gallon of stripper. Brush the stripper on nice and thick. Then cover the whole area with strips of saran wrap. Come back many hours, or even days later. Lift the saran wrap and most, if not all, of the paint/primer (even some bondo) comes up with it. If the timing is right, it sorts of bonds to the saran wrap instead of the car. The saran wrap holds the chemicals down in the paint where they can work, instead of evaporating. Fumes are cut by probably 95% or better.

Works for me anyway.
DG

I just did something similar with naval jelly rust dissolver, though I used old plastic tarps. Worked much better, I will remember that when it comes time to strip my B coupe.