Acetone or Mineral spirits?

[Finallybuyingaboat]

I am going to be repainting the deck on my boat and had intended to use acetone just prior to priming to get all of the dust off. However, I have read that acetone turns gelcoat into mush. I am wondering what other product could be used which may be safer around gelcoat. Also, I have a teak rubrail, and need to prep that prior to applying cetol, and i am pretty sure I do not want any acetone anywhere near the hull if it has such an adverse affect on gelcoat. Ideas?

[DrB]

If you are looking just to get the dust off, a weak soapy solution with a light scrub/mop followed by a rinse should suffice. Why use acetone?

Acetone shouldn't turn gelcoat into mush if you just use it to wipe it down. Acetone is very volatile, it really won't sit on the surface for more than a few seconds in any time of temperature or breeze.

DrB

[kwaltersmi]

Interlux sells a couple of products called "Fiberglass Solvent Wash", "Fiberglass Surface Prep" and "Brushing Liquid". I think any of these should work for your application.

I just finished painting everything on my boat above the waterline. I just used clean warm water and several clean rags to remove the sanding dust.

[timebandit]

Just before painting always, always use a tack cloth.

[NOLAsailing]

STOP!

All paint systems I'm aware of (Interlux, AwlGrip, AlexSeal, etc) have specific solvents for prepping the surface. It's an important step - please don't skip it (yes, they are way more expensive than just acetone). If you're just removing bulk dust and residue, then go ahead and use acetone or mineral spirits (neither will damage the gelcoat), but follow up with liberal use of the manufacturer's recommended solvent.

[DrB]

For getting dust off, why is everyone telling the OP to use volatile and flammable solvents? General deck cleaning and dust removal should be done with a weak soapy solution and rinse.

The is a difference between dust/dirt and grease/wax and residual adhesives. If the OP has dust/dirt, use a weak soapy solution with some scrubbing action and then rinse well with water, allow to dry thoroughly, then follow with the paint prep solvent for what ever paint system that you are using. If there are areas of residual adhesive, grease, or wax, hit them with a cloth soaked in acetone or mineral spirits first. No need to do whole desk in acetone or MS .

The paint prep materials do have high flash solvents in them and surface etching materials, but they also contain a small amount of "paint/tie coat" that will bond to the cleaned deck and help the topcoat bond better. You need to do this step, as NOLAsailing points out, to ensure adhesion of the topcoat.

DrB

[BenthosCritter]

Finally,
Acetone does not dissolve gelcoat...period. NOLASailing is correct. Use the manufacturers surface prep.

Good luck with your project.

David

[Maine Sail]

Originally Posted by Finallybuyingaboat

However, I have read that acetone turns gelcoat into mush. Ideas?

This is a 100% bogus information! I have been using Acetone on gelcoat, as a wipe down / prep agent for over 30 years and have never once seen my gelcoat turn to mush.

If you pour it on the surface, and let it just sit there, it will eventually do some damage but why the heck would you do that? It will do no damage wiping the surface with a rag doused in Acetone. MEK is a another good wipe down agent that evaporates a little slower. I don't like oil based solvents such as straight mineral spirits because they can leave an oily film..

If you're still concerned about Acetone you can pay big bucks for Interlux 202 Solvent Wash or Pettit Fiberglass Dewaxer.

202 is a mixture of a bunch of potent chemicals like MEK, Cumene or isopropylbenzene, Xylene, Naptha and Cyclohexanone which is a similar industrial solvent to Acetone...

[DrB]

Acetone ((CH3)2O) is chemically very different than Xylene, isopropylbezene,and Naptha. Acetone (and MEK and Cyclohexanone) are ketones, the others you mentioned are alkenes or in the case of Naptha a mixture of alkenes and alkanes. Acetone and MEK are low boiling very fast evaporting, were as the others are not.

I still advocate using water/soap as the initial process for getting rid of the bulk sanding dust/dirt, then following it with a solvent wipe (acetone or similar) for spot greasy or oily areas, then your paint prep fluid the whole, and lastly the topcoat paint.

DrB

[Quickstep192]

If, after all that work, there was a problem with the finish, I would want to be able to go back to the manufacturer and say that I had used all of their products just as they described.