tips on finishing the bottom of my CSR.

[Silas_53A]

I've searched as much as I can and can't find anything. But im working on my CSR and about to refinish the bottom. It just has its original varnish/epoxy finish on the bare wood, no sanding or anything. I would like some tips on what to do. I currently plan to pour some fiberglass resin out on it and level it out. then flat block sand it to like 4-500 grit.

what do other people do?

[T Chance]

On my Pro runabouts I flatten the bottom with a block of foam glass insulation; aka rottenstone or stinkblock.

[Silas_53A]

do you flatten the wood itself? then just epoxy/varnish over it? or do you use like a fiberglass resin, then sand it?

[pops67g]

West System only

Forget fiberglass resin and varnish altogether. All you need is to coat the bottom with epoxy resin. Check the bottom with a straightedge for flatness in all directions on the planing surface. If you find an uneven condition you must decide if you have to shave down the high spots OR fill the low spots OR a little of both. Use epoxy resin with some filler mixed in (I use the high density 404 filler). A long sanding board works fine. The epoxy with filler sands a little hard, but the results are a tough bottom when you're done. I never use varnish on the bottom as it makes repairs a pain when you have to strip off the varnish to add epoxy. Also the finely sanded epoxy is a smoother, faster finish anyway.

[bill boyes]

Silas, DO NOT APPLY POLYESTER RESIN OVER EPOXY!!!! It will not cure.

[T Chance]

do you flatten the wood itself? then just epoxy/varnish over it? or do you use like a fiberglass resin, then sand it?

Epoxy!

[Silas_53A]

Thanks everyone! I will be grabbing some epoxy tomorrow, and getting this all done. hopefully it will all be cured and the sanding can start (maybe finish??) saturday. and painting the rest of the boat sunday and so on.

[Silas_53A]

dad grabbed 403 filler by accident, how much of a difference would that make? how necessary is the filler?

[pops67g]

Fillers are rather specific

403 filler is designed to be used in glue joints to increase "grab" between pieces. 404 is high density for building up surfaces. I think you should make an exchange if you want good results.

[HydroKyle93R]

Also, to determine whether you have high or low spots, that a pencil and mark the entire planing surface. this way, when it is sanded, the bare spots will show what is high and the remaining marked areas will show what is low. I"d recommend beginning to lightly fill the low areas and try to eliminate them altogether. Just remember you want the back 30 or so inches totally flat, both with respect to longitude, latitude, and diagonally.

[Tomtall]

Sanding

I was given this tip several years ago by a veteran racer and it has worked very well over the years for making boat bottoms VERY flat. The sanding paper is a belt sanding roll cut to length to cover the 6" u-channel. Use 3M spay glue and you can make good time cutting a bottom down flat. We touch the boats bottoms up every spring just to make sure things are still flat.

Good Luck !!

[Tomtall]

Pour the bottom

Save yourself alot of time and just pour the bottom with epoxy. Tape the edges of the bottom off. Make sure you clean the area where your taping with rubbing alcohol before sticking a good grade of masking tape down. Level the boat on the saw horses tho get the boat perfectly level both front to back and side to side. Mix up a couple quarts of epoxy resin. Pour it on and brush it out. Let it flow out and check for pooling in corners and sides of tape. Adjust levelness as necessary to get even build. Allow to cure and set for at least two days prior to sanding.

Good Luck !!

[Tomtall]

Check flatness

One more tip. We use a straight edge made by "Blue Point" made for check cylinder heads on cars. Approx. 24" long. Take a piece of notebook paper and go over the running surface of the bottom looking for low spots. If the paper goes under the straight edge it's NOT FLAT. Keep working the bottom flat till the paper will not go under the straight edge.

[Affholter66]

GREAT Tips Tom...I've saved your posts!! Thanks

[Jakeroub]

This is a great post, can it be made into a "sticky" or something?