Chemical Stripper Advice Needed!

[Bob Sanders]

I just built a desk, messed up the lacquer twice, used lacquer thinner to remove it twice, and then tried a catalyzed varnish spray-on. Unfortunately, the varnish interacted with my old lacquer (I think) and beaded up... it looked like fish scales when I was done...

http://farm4.static.flickr.com/3276/2452960200_1c5bcbd3f2.jpg?v=0



Now what I'm trying to do is remove the catalyzed varnish with a chemical stripper.
http://farm3.static.flickr.com/2329/2464460958_50500fe6dd.jpg?v=0


It appears to be working well, but I am nervous about starting the process again. I do not want to do this a FOURTH time! With my previous coats of lacquer, lacquer thinner, varnish, chemical stripper, xylene, etc. I am having a horrible first attempt at finishing.

What I am wondering now is how to reduce the possibility of messing up the next attempt. What tips and tricks of the trade can you give me? What shoudl I look out for? What steps should I follow from this point?

Any help you could offer would be tremendously appreciated.

Additional information to help you:
I have been using all oil based products.
Oil based gel stain.
Oil based lacquer.
I don't know exactly what the catalyzed varnish was... but I know it was supposed to be VERY durable, more so than the lacquer.
The chemical stripper was pretty ordinary, oil based, I think it said 'paint stripper' on the label.

I am going to finish up the stripping tonight. I figured I would sand it a little first before I put another coat of stain on it and then tried to re-finish.

Thoughts?

[Steve Schoene]

Let's be more specific about the products you used. What brands and exact names of products. For example, there are numerous kinds of paint stripper some have wax that needs to be dealt with fully before anything is applied on top. The varieties of catalyzed products are legion. Some require specific sealers--named by brand and model number.

The solvents in ordinary nitrocellulose lacquer are considerably stronger than those in many other finishes and that severely limits where they can be applied. It may well be that the lacquer solvent interfered with the binder of the stain. Just because they are oil based doesn't make them compatible by any means.

In fact I think it is better to think of lacquer as "solvent based" just because it calls attentiion to the particular needs lacquer has because of its stronger solvents. And catalyzed products have very specific requirements as well both for compatible products and for safety procedures. Their requirements must be followed to the letter or disaster can follow, as you have observed.

The first thing with any product is to read the technical data sheet which will often explain what other products are compatible.

[Bob Sanders]

Steve,
You are obviously incredibly knowledgeable on this topic. Everything you said makes perfect sense to me... but I am left wondering if I still need to be concerned about the compatibility of the lacquer/catalyzed varnish if I've applied a chemical stripper, sanded it down a bit, and re-stained. After I've re-stained, should I ONLY have to be worried about the stain and catalyzed varnish compatibility?

Thanks!

[Steve Schoene]

I think, but can't be totally confident, that if you have thoroughly stripped, and neutralized the stripper, making sure you have removed all residual products, plus sanding you should be able to stain and then apply a top coat worrying only about the compatibility of the top coat and the stain.

I would only use stain specifically recommended by name by the maker of the catalyzed topcoat. That means you must find out exactly what product you are using and have the technical data sheet for that specific product.

Reading that sheet may also make you wonder about whether it is safe to use. Some of these things typically require full fledged spray booths, and some of them even need booths that capture the solvent fumes rather than releasing them into the atmosphere. The first costs thousands of dollars and the second many tens of thousands.