mold from old hull?

[1970kayhydro]

would it be easer to just wax up the hull and use it as a mold?

 

[i386]

Re: mold from old hull?

You would need to use your existing hull as a plug to make a new mold, then make a new hull from the mold. You would spend a lot of money in materials. If you were lucky, you'd end up with a new hull that still needs stringers. Not very practical for a one-off imo.

 

[1970kayhydro]

Re: mold from old hull?

but if im reglassing the hull, why not do the top/? it would be a little biger naybe 1/2"

 

[redfury]

Re: mold from old hull?

If you are replacing the top with a one off by using the original top as a mold, then you are basically using the top as a plug and using a mold as a finished product....does that make sense? The new "top" would be the width of the old tops fiberglass larger than the old one as far as how it would fit onto the hull.

 

[ondarvr]

Re: mold from old hull?

Without making a plug first, you would need to do a tremendous amount of fairing to make it look good.

 

[Chinewalker]

Re: mold from old hull?

And the hull and deck are currently unsupported, showing 30+ years of nicks, dings, imperfections, etc. so all those would show up in the mold. You could spend a good deal of time cleaning those up, bracing and reinforcing the hull and deck so that they are straight and true and in the end you will have invested several times the money, time and frustration into a mold that you then have to go back and make a new hull from. MUCH, MUCH easier to fix what you have...
- Scott

 

[Bondo]

Re: mold from old hull?

would it be easer to just wax up the hull and use it as a mold?

Ayuh,...

But only if you plan to build a couple Hundred of those hulls....

Just the Molds would run you probably 10Xs the work,+ money it'll cost to fix what you've got...

 

[jonesg]

Re: mold from old hull?

Not easier or cheaper by a long shot , but interesting.
I like making molds but only if the plan is to pull several peices from it.
And yeh you'll need to restore the finish to a mirror before waxing starts......or the part will look like junk and probably damage the mold after a couple of pulls.
Better to mold your own unique design.

 

[1970kayhydro]

Re: mold from old hull?

so i guess i will jut forget that idea..

thanks for the info!

 

[oops!]

Re: mold from old hull?

i know bud......its hard work.....we have all done it....some more than once.

a lot of people give up on there projects, some for different reasons.....but going to bed with a sore body every night is a good reason to tip the scales....

keep atter.....the next phase is right around the corner......actually....i consider my time working on on the boat very relaxing.

 

[1970kayhydro]

Re: mold from old hull?

yeah this thing has hardened resin goobed up real thick under where the wood was flat and around the stringers. the sanding is going painfully Slow. at least i can save time by not taking pictures of the lack of noticable progress im about half way down one side from the center to the sponson... OOPs, its not going to the dump any time soon, if i get frustrated to that point i can throw it all in the barn and come back to it later. the g/f is whining about parking out in the snow.

 

[oops!]

Re: mold from old hull?

thake that grinder with a 7 inch rubber backing pad....(dont use a 7 inch on a cheap 4 inch grinder).......use 24 grit resin backed paper.....and go for it....

youll be done in a few hours ....(dont go thru the boat).....remember....you are just ruff and scuffing it hull, to prep it for new glass......

by using the edge of the grinder....or a cut off wheel....you can get all the wood slivers out......dont get too anal ! (you could be there for three years)


using a small grinding disc.....(not the 7 inch flapper) it took me 5 hrs to grind my entire inside of the hull.... (rough and scuff)

it may help to get pics hydro.......you might be thinking too much detail....(called getting anal )....and that will slow ya waaaay down every time.

cheers
oops

 

[1970kayhydro]

Re: mold from old hull?

Alright here are two pics. The area that is cleaned off is only about 1/8" thick and Im worried that the hull will warp or break if I get the whole thing down that far. Should I do one side front to back and lay 1708 all the way then do the other side and then do the middle stringer and glass it in? Just work my way out? And no thats not a bench seat, i put that there to kneel on and saw out the middle stringer..

 

[1970kayhydro]

Re: mold from old hull?

Cracks showing on the bottom.. After a good look over in the daylight I found this..

 

[i386]

Re: mold from old hull?

Don't worry, you can fix it. It's hard to tell but I think I see some crazing (spider cracks) and a larger crack in the glass. For the larger crack, just grind out all the bad glass. It's going to make a hole, but that's ok. Give the perimeter of the hole some taper.

I did the same thing in many places on my hull so here's the method I used...
Once I had the bad places ground out, I put strips of clear packing tape on the outside of the hull. I did it in such a way as to maintain the curvature. Then from the inside, I made my lamination alternating CSM and cloth. If you have 1708 that's probably even better. You can change the orientation of each layer for even more strength. Once the resin cures, you can peel off the tape. The resin won't stick to it and you won't have to do a lot of work to the outside to hide the repair. I used epoxy resin, but I would think either type is fine. You can see some examples of what I'm talking about in my photo gallery. I wish I had gotten some better pics of the repair but maybe you can get an idea.

BTW, your grinding work looks good to me. Just try not to go into the cloth. Also, you only need to grind places that you intend to put new glass or want to have a nice finish.

When you get to the point you're ready to do the outside finishing work, make a post about those spider cracks. Mine turned out fine, but I ran across some info after the fact that might have taken a lot of time and work off of the process.

 

[i386]

Re: mold from old hull?

One more thing I think I should mention about the spider cracks. If your boat is like mine, you're bound to find some really bad ones. (I have plenty of pics of bad ones lol). You'll want to go ahead and grind those out. I actually found water soaked glass in mine. You might end up making some new holes in the process is why I suggest going ahead and taking care of those. You'll be really ahead of the game if you can make all the repairs from the inside. You can make the repairs as thick as required and not have to worry about hiding a bulky repair on the outside of your hull.

Seriously, don't sweat it. If I can make all the holes in my old boat disappear, anyone can.