Board conversion advice

Hi,

I'm expecting some negative responses here.....but..... I've been thinking of widening an 2003 75L Evo Starboard board in a similar way to what was done by someone else on this forum and was after some advice.

This is the previous conversion I saw:






30mm x 2 inserts of foam I have roughly calculated will increase the volume by about 12.5 L = 87.5L board and width from 56cm to 62cm

50mm x 2 inserts of foam I have roughly calculated will increase the volume by about 20 L = 95L board and width from 56cm to 66cm


My Questions:

Foam- Bunnings sell insulation XPS FOAM, would this be ok to use?








Air movement in the board.
By cutting, inserting the foam and gluing it in place is there any issue that this creates three chambers within the board and air pressure can't be released between them to the bung ?

Any comments or advice?

Thanks
Rob

I'm the guy that widened that board. There is a lot of work in it.

I can't remember too much because it was a while ago, but I think now I would just cut it down the middle and do the widening in one piece and replace the finbox and mast track instead. You will probably want to change the footstrap inserts anyway.

The styrofoam in mine is made up of layers of foam about an inch thick laminated together (thanks liteneasy!). The 2-part pour foam was to glue it together, as there is not much that sticks well to styrofoam. There are sections that are effectively open (no glue inbetween the styrofoam) to allow any pressure to leak from one part to another.

As Mark has said, you need to laminate divinycell over the top. Use a router to create that recess for the divinycell.

I'm sure that foam will be fine, it's a bit heavy though, I calculate that to be 32.87Kg/m3. Most boards only have 13kg/m3 for the core foam. (The d-cell is usually 80kg/m3). But if it's only 12.5l, not a big issue. It also looks like closed cell foam, so you need to do more than just leave gaps in the adhesive. Mark's idea of a tunnel through it connecting to a single bung is a great idea.
Because it's closed cell and medium density, it's the ideal foam for sinking boxes and plugs into. it will support them better, and if there is a leak the water won't travel anywhere. So I'd be going with the suggestion of making one cut down the middle, and if you have to redo the footstrap plugs put some of your foam around them.

Because it's medium density foam, where it's not an impact area, you could probably get away with a couple of layers of 200gm carbon instead of a d-cell sandwich. But under the feet I'd still use a d-cell/carbon sandwich. So it's possibly easier to do the d-cell sandwich all the way.
And when you route out the d-cell recess, go into the original board as well, without cutting into the bottom layer of cloth. This takes some fine adjustment of the router, but if you get an overlap on the bottom layer of cloth it will be a much stronger job.

I would drill holes through the xps so air can move through the whole board.
Back in 2009
www.seabreeze.com.au/forums/Windsurfing/General/Ive-changed-MY-MIND/?page=-2

Seems like a lot of work to do, and what if it doesn't come out right. Unless you are a pro in board reconstruction, I wouldn't even attempt it. What you are attempting to do is very specialized. That's why there are board shapers and designers. Not trying discourage you from this project. I personally have a lot of experience with fiberglassing sailboards and sailboat repairs, and I can tell you that I wouldn't even attempt that reconstruction if that was my board. I would spend the money for your board conversion towards a board that is made to the specs of your choice and ready to sail. You will have peace of mind when you are on the water. Good luck with what ever you decide to do.

By chance if you happen to have a physics, chemistry backround, or you are a chemical engineer, this job will be easier to successfully Cary out.

not sure why photos are upside down ?

A physics and chemistry backround I believe can be a helping hand especially when you are dealing with mixtures of chemicals such as different kinds of resins, epoxy and hardners. It's important to know what kind of resins work best with other materials used as well as their chemical reaction to different foam cores, open and closed cell, as well as inserting additives to increase or decrease viscosity of resins, and what chemicals will bond with desired foam and which will not, or melt the foam intirely. Knowledge of appropriate amounts of mass volume of foam needed for desired amount of liters necessary . The list goes on. There is a lot to know about this stuff.

I am impressed with this guy's work, and some people just have a nack for it, or have been brought up around it and learned from someone.

Another interesting thing is, those who have completed several successful board repairs, beleive it or not already understand the chemistry of these different chemicals, maybe not all of us understand it scientifically, but we know what works with what by trial and error. That's basic chemistry. Then understanding the foam issue and quantity needed is the physics part. It's pretty awesome actually.

I am just another guy with another view on this topic, take it for what it's worth. There are a lot of great ideas here. Some eclectic, some not, some creative, some scientific, some with common sence, some that got lucky. Bottom line is, everyone here brings great knowledge to the table which is extremely valuable to all of us here.

Given all you are doing is cutting, gluing back together with a spacer, then replacing existing divinycell with the same materials and using the same stuff (epoxy) then I think it is a skills and commonsense thing - not a chemistry degree thing.

It may or may not work, but to have a $200 board, add $100 materials and have a go ....... if it works it is well worth the effort.
If it doesn't well you had $300 worth of fun, and in motorsport that would be about 10mins.
Then u can salvage all the inserts for when u build a board one day.

Go for it.

Where is a good place to buy fin boxes?

Current plan is to make it a tri fin. Salvage the current single fin box and add two boxes to make it a Tri.

Is it best to go for slot boxes or any other suggestions?

Thanks for all the previous comments.

If i was doing it ..I would make a cut on each side of the mast track and fin box cutting a 40 mm piece out ,then adding your extra piece in the middle
this way you can re-use the fin box and track ,cutting down in cost .you may not have to change the foot straps at all ..
just a theory ..
you may not have to re- paint ...having a nice racing strip right up the middle .
Wow.
i wish I could have a go with the skill saw.