Media blasting bilge and hull

[Kiloecho]

I've read many restoration forums where hours and hours were spent grinding the hull and bilge prior to stringer and floor rebuilding. Has anyone had any success using blasting media?
I found this on the net along with many fiberglass auto information. It seems like a great way to speed up the process. What are your thoughts? http://sodablastboats.com

 

[jbcurt00]

Might read this at their site:
http://sodablastboats.com/safely-strip-to-gelcoat/

Soda blast strips PAINT, not the gelcoat typically found in bilges or on all of the exterior surfaces (and most of the surfaces that can be seen or touched during normal operation) of a boat. . I would guess it would strip 1 part bilge specific paint that is sometimes used instead of gelcoat, like BilgKote. Not sure off hand if any makers use a bilge paint, but some probably do. Some of them might use 2 part bilge specific paint, but I dont know if thats even available. If it is, soda might or might not take it off..

Ok, so now we know media blasting wont remove gelcoat, but what about fiberglass? Nope.

Might slightly roughen the surface of fiberglass, just like it would gelcoat, but I'm not sure it provides a surface sufficient adequate bonding of repairs or newly added stringers.

Part of the grinding is to remove any remaining fiberglass tabbing to provide a flatish surface to put the new materials on AND expose good clean fiberglass to bond the new work to. IMO, none of that is accomplished using a soda blaster.

If the exterior gelcoat is in good shape, but you want to change the color, maybe, but only in place of sanfing the surface to be painted. Not in prep to re-gelcoat.

Yep, grinding glass sucks. Not anyway around it as far as I know.

Looking back, I suspect you were talking about blasting once the stringers and all are out. Just as the final prep for new glass. Initially I was thinking you meant as a tool for removing the stringers and etc. Pretty sure you didnt mean for the initial removal.

 

[gm280]

As much a I dislike grinding in prep for a boat refurbish job, I, as well, can't see media blasting accomplish much of anything but paint removal. If it won't do anything to fiberglass, then it is not going to make a boat rebuild job any faster. You'd still have to grind the surface to remove the old fiberglass to create a solid fresh surface to attach new polyester material too again. But I haven't seen this media blasting in work and therefore that is just my opinion... JMHO!

 

[DeepBlue2010]

The first layer of any subsequent application of fiberglass to an already cured laminate attaches itself to the old laminate through a mechanical bond not chemical. The reason for grinding is not only removing any contamination on the surface (wax, etc) but also and more importantly is to tear apart some of the old glass fibers so the new glass attached itself to them for a strong mechanical bond. That is why light sanding while capable of removing contaminates is not what you what to use before glassing. You need to get deep to those fibers and tear them apart (microscopically speaking, of course)

 

[Kiloecho]

Gentleman, thank you for the feedback and a great discussion. I had my doubts about it beng an effective cleaning prep. One worry I had was pushing grease and contaminates further into the fibers.

In the late eighties I was a kid maintaining a small business jet out of Will Rodgers in OKC. AAR, our hanger landlord had a propeller shop in the next hanger. They were always good about letting me use the plastic media blaster for car projects I had going on. One day I degreased an alternator off my Buick station wagon and then throw it in the media blaster. It cleaned the exterior up like new. After blowing the plastic dust out I reinstalled it on the car and drove it another five years.

Plastic media is gently stuff snd will not peel the alclad of props and aircraft aluminum. I was hoping to hear soda or walnut media would be aggressive enough to keep me from having to grind the Arabian.

 

[gm280]

Gentleman, thank you for the feedback and a great discussion. I had my doubts about it beng an effective cleaning prep. One worry I had was pushing grease and contaminates further into the fibers.

In the late eighties I was a kid maintaining a small business jet out of Will Rodgers in OKC. AAR, our hanger landlord had a propeller shop in the next hanger. They were always good about letting me use the plastic media blaster for car projects I had going on. One day I degreased an alternator off my Buick station wagon and then throw it in the media blaster. It cleaned the exterior up like new. After blowing the plastic dust out I reinstalled it on the car and drove it another five years.

Plastic media is gently stuff snd will not peel the alclad of props and aircraft aluminum. I was hoping to hear soda or walnut media would be aggressive enough to keep me from having to grind the Arabian.

Ha, do a little section and see. We can talk about it all day long. But actually doing a little portion will show one way or the other. You could find it works like you wanted it too... :noidea:

 

[Ned L]

I think the main reason media blasting is not really used is because the equipment is not readily available to do-it-yourself'ers like the people here.
When it comes to "media blasting" there are so many types of media available, it is just a matter of choosing an appropriate one. Years ago when I worked at a shipyard building commercial fishing boats the blaster we had held 600 pounds of media ( we used "Black Beauty", a silica abrogate) that if used on a glass hull could have put a hole right through it in short order. It certainly would have provided a surface that is rougher than any grinding job.
Again, it's just matter of selecting the tools (blast equipment and media type).