bottom blasting help

[CaptDana]

Well faithful- the 28 is back together- floating and running charters- I am getting ready to shift gears and start my 25b-- hardtop-- I am planning on going with a backet and single 225 Merc which I have already purchased both the bracket and outboard. I was looking at my bottom and want to do this boat 'right' the first time. I am planning on blasting the bottom and then filling any voids with epoxy before barrier coating and putting on VC- Any input as to what kind of media to use when blasting the bottom? I am planning on taking it easy on the bottom( I will be blasting it myself with a small pot blaster) Also- what filler to mix with the epoxy to fill voids( I get my materials from Fiberglass coatings)

Thanks in advance
Capt dana

[CaptPatrick]

I will be blasting it myself with a small pot blaster

Dana,

Blasting the bottom of a boat can be a real task with a small media blast rig & especially without a media recovery system... Are you going to be doing this in a boatyard or on your own property?

Soda blasting, (wet), takes a special, more sophisticated, & costly rig. Best media, both from a gentle & cost stand point, for a dry rig is crushed walnut shell. But you need to be able capture & re-use the media, or you'll go through a massive amount of material if it only goes out the nozzle once.

You'll need to spread a large clean catchment of some kind under & around the boat. My 60 lb capacity blaster will only hold about 35 lbs of walnut shell because of the light weight per cu/ft of the material. You'll go through that volume in a very short time -- minutes... The thickest black visquine available would probably be my choice for a catchment. This is my reason for asking about where you'll be doing the work. Walking around on plastic sheeting laid out over the standard boatyard gravel is going to turn it into a sieve. Over grass or dirt, it'd be OK with soft soled shoes or with just heavy socks on.

You'll also be eating up a lot of compressed air real quick, so you'll need a high delivery compressor to keep up.

Open media blasting needs to be done with proper body cover. The bounce-back will be strong enough to sand down bare skin. A full head shield & heavy gloves are a must.

Br,

Patrick

[Raybo Marine NY]

as capt pat said you need a rather hefty compressor to blast a boat.

This is one of those times its best to pay someone to come, tarp the boat and ground off, let them get messy and take thier mess with them.

At about $25-$35 per foot its worth every single penny.

[DRIFTER31]

I just went thru trying the soda/pressure washer rig and it works a little. Sandblasting works but is grueling. I found the easiest is to use good stripper[not biofriendly] and let it sit then pressure wash. It will take 3 times but by the third time its all gone. 3500lb pressure washer. Much less a pain than sandplasting. Troy 31Tiara"DRIFTER"

[CaptDana]

I will be doing this at my friends place-( he has 6 projects in his yard) We were planning on tarping off and using visqueen on the ground(grass--soft) to help recover the media- Where is the best source for the walnut shells?

THanks
Dana

[CaptDana]

Also- It appears that my bottom is not layered with a ton of paint---about how many lbs of walnut shells will I need for the 25 bottom?
Thanks

[randall]

i did about a third of mine (just the bow area)with four im guessing 60 pound bags of shells. recapturing them is not easy. a friend did something interesting ...he used fine sand at low pressure and kinda peeled the paint off instead of blasting the shit out of it....im about to blast 40 years of grime off the inside of the engine hatch covers........and the lawn furniture at the same time.

[CaptPatrick]

Where is the best source for the walnut shells?

Dana,
Best I've found is Harbor Freight $1.00 per lb + shipping... I'd get 100 lbs.

Br,

Patrick

[CaptDana]

Capt Pat
Thanks- Harbor Freight has a place 30 mins away. Gonna give them a call and open the wallet
Thanks

[STeveZ]

Regarding filler, I used 3M Marine Vinyester Filler on the recommendation of my boat yard. The reason given was that it will not absord or retain water.

[scot]

Randall,

instead of blasting the shit out of it

That would take all the fun out of it, struggling with the hose, seeing crap flying all over the place, etc.