Wooden Surfboard Finishing / Sealing

SNight · 15 May 2010

I am planning on making a hollow wooden surfboard. Consisting of a plywood inner frame, similar to the way an aircfaft wing would be constructed, then skinned with 6mm thick strips of western red cedar.

I was wondering what would be best to finish the board with? Someone with experience in traditional boat building maybe best to answer this for me.

I have built one before, and decided to cover with fiberglass cloth and epoxy resin but was an absolute nightmare getting the mix / ratio right, and also, using in the correct temperature, which was difficult in the winter! So took ages to cure. If possible I don't want go down this route again. So any alternatives? Oils or Varnishes maybe? What would be used on a wooden boat or canoe?

wills-mill · 15 May 2010

I've milled some local Western Red Cedar strips for a very good amateur board maker, he'd used a very light fibreglass cloth/tissue and epoxy finish as you've tried, and I feel that this is more or less the only sensible long term solution to a board that's going to get wetted and dried and be bumped around.... The fibreglass has actually got a fairly important structural role to play but was almost invisible in the finished product when wetted with epoxy.

I'll see if I can find the wooden surf board forum that's out there- it's been a while....

Yup! Tree to sea

http://www.grainsurf.com/forum/

SNight · 16 May 2010

Thanks wills mill. I realize thats prob the best option to do, and if i decide to use the fiberglass cloth I think I will get someone who has experience of using it to do it for me.

I have found a product that a lot of people seem to use on canoes and waterbound products called Varnol. Supposed to be a mixure of varnish and oils. Has anybody used this before?

kasandrich · 16 May 2010

I used to build model gliders and the fibreglass and epoxy coating on the outside adds heaps of strength not just waterproofing.

It pulls it all together supporting and reinforcing the joints and adding torsional stiffness.

I think you would have a big strength issue if you didn't use it.

What problems did you have using it? Temperature is easily solved, either do it when its warmer, or in a heated workshop.

Mixture is easy, just follow the instructions.

Application is straightforward, using a paint brush wet the object with epoxy, then lay the cloth on and stipple it with the brush, aim to wet the cloth right through and remove any air bubbles, there should be no surplus epoxy. This will give a strong flexible casing.

Are you looking for an opaque finish or a clear finish?

For an opaque finish, lightly sand, fill and paint.

SNight · 16 May 2010

It was the first time I ever tried using it, and think I mixed it wrong. If I try it again I think I will have a go on a scrap piece first. I am a Joiner / Cabinet Maker so my woodwork is fine, but no experience in glassing.

Can any one reccomend a good fiberglassing system? I have seen some people using the West epoxy resins, Could this be used in conjunction with cloth? Also to get a high gloss finish do you have to use a 'hot coat' and how is this done?

Thanks for the reply Kasandrich. Did you use hot coats? I am looking for a clear high gloss finish.

Boatfixer · 16 May 2010

Your best bet for constructing this would be to use epoxy to glue it together as well as a coating. The main brands are West and SP systems. I find that SP has the edge as a coating resin and is slightly cheaper as well but I do tend to use more West purely because I have been using it since the seventies and am used to it as a product....

Re measuring the ratios for both systems you can get calibrated pumps - 1 squeeze of resin to 1 squeeze of hardener. Easy to get right but a simple hint would be to take one pump of each alternately - this gives the pumps time to re-fill and means you don't lose count when mixing larger batches. Heat is as you say critical. In winter a plastic tent and a small fan heater can give you enough to get the resin going.

As a finish coat you should really be using a different hardener but as most epoxies are not UV stable I would recommend using standard fast hardener and hot coating. When cured I would then rub back with wet and dry to remove the amines from the surface of the epoxy and applying 2 or 3 coats of 2 pack varnish to give both shine and UV protection.

Hope this helps
Graham