fibreglass on stainless steel ...

I am wanting to lay up a mini curved fin panel on this ....


has anyone laid up cloth and resin over steel ,


  if so , did you HAVE to use a wax release agent to get it off ? [when I lay up fins on glass , I can just prise them off the glass pane with a paint scraper , I am hoping to be able to do the same with the stainless steel , but I'd hate for it to stick and ruin the work Marty put into making such a smooth fin plug ??


  cheers guys for your help .


[I did the 'wax / greaseproof paper option on my ['bucket-curved']  mini curved fin panel ]



oopsy !!


"this"   =



cheers !


Wax it, (with a high quality car wax) and rub it out 10 times, and it will be ready.  To remove the fins once cured use a plastic wedge, a mallet, and air pressure.  Consider that curing resins shrink, and some more than others, use a good quality epoxy. 

thanks for the reply Ghetto !

I am using polyester resin on all my fin panels , by the way . I will do a test on another small piece of stainless steel , I think , just to see what will happen without release agent .

I think the challenge will be laying it up on the curves . [The previous one I laid up on glass [flat] , then transferred it and taped it to the bucket when it was still kinda tacky ]

I guess boat builders and others do this [lay up curves ] regularly ?

…‘Doc’ , where ARE you ?!

cheers !


Hi Ben -

Make it easy on yourself... take ghettorat's advice.  You don't want to gouge your fins taking them out of the mold.

Maybe set up a clay or plaster backing/holder and put it all on a vacuum table without puncturing bag?  Run double stick butyl rubber tape around the edge of the table, apply single sheet vacuum membrane and suck the air out with a pump - be bubble free.  Something as simple as a pane of glass can serve as a 'vacuum table.' 

Get fancy and vacuum infuse? 

To save weight - perhaps place a thin foam or Balsa insert between your glass layers inside the vacuum bag?

A Dremel tool with a reinforced cut-off wheel makes quick work of excess flashing after it all cures.

That looks like a fantastic mold!

Is that what it is ? ( the mould ) 

Sounds like a great way to do it Ben. dont forget the pics !!!!

I’ve used pam(cooking oil spray) on flat surfaces, but not something curvy like that.

How The heck did you make that Stainless Steel Mold? It looks like it was stamped.

Ghetto is right, wax it till it shines. This will show that the grooves in the stainless are “filled” so the resin cannot form a mechanical bond.


How The heck did you make that Stainless Steel Mold? It looks like it was stamped.



Well, I will ask Marty next time I see him , but three words ...'stainless steel pipe'.


he said it took him about half an hour , per fin , to'FIN'ish them off . Marty has made two different sized pairs [ie: four fins] .  So , that was two hours of his precious time taken up with it , so far.


 Plan B , when he gets time , is for him to make one at LEAST 8 x 12" rectangle , with one long tab , easier for laying up a panel on . Then I can cut out lots of different templates . This would make things  easier [for him] , and quicker [for me , for fin layups].  He has just been commissioned for his first ever  long-term , large sculpture project , so it may be a while till he gets to do that , though..... ? to be continued ? ....


  cheers !



Meanwhile ( from 'Stingray's epic ' what are you working on ? ' thread ) , THIS is how I added a tab to my previous curved panel.


'Wax' [greaseproof] paper , a wooden ruler , and masking tape were used. I added one layer of 6oz cloth at a time , then brushed laminating resin on each layer....





 It's a learning'curve' , but for the next one , I will use narrower masking tape , remove the tape when glass is 'half-gelled' , then CAREFULLY add the remaining layers of cloth WITHOUT tape , so there will hopefully be very little 'ridge' to sand down , on the base of the fin . Maybe adding a complete , panel-sized piece of glass at a time could be the way to go , come to think of it ... so ,  then I can build up the fin thickness , AND make a long tab at the same time , THAT way !!

 cheers !

 ben  the fin-tinkerer [?'finkerer'?]

thanks Marty !

he whipped this up for me yesterday , while his kiddies were sleeping ...

[it's only 3 1/4" deep [!!] , but with a 7 3/8" base ....  nice to have the long metal tab to lay up fibreglass and catalysed resin on ...]






and , 'Plan C'  [to get a BIGGER curve , that  is ]...


 the ubiqitous 'Milo' tin [" it's marvellous what a difference MILO makes !!"]....






the next step will be to cut off the ends of the tin. [And , clean off the Milo residue ! ]


then , with metal snips , cut down the seam , to get the one piece of curved metal , and  bend one long tab into it .... be continued ...


  cheers guys * !




* ...WHERE  did Rachel and 'ethereal prodigy' disappear to ??  .... ANYONE KNOW ?

Hi Ben, Tridrles has made curved carbon fiber fins using a simple foam pattern and a vac bag.

I’m getting stuff together for you to make fins from. I have some koa veneer that you can sandwich between layers of glass. I haven’t gotten that nice big thin piece of wilwili for you, but I have a bunch that we already cut into fin shapes. Based on my first try, they’d have to be sanded thinner to make good fins. I’ve made several glass panels, but I haven’t gotten around to cutting them out and foiling them. I really want to use Bernie’s expensive vacuum attached sander, but haven’t made the time to get out there.

When I’m ready to send it, I’ll PM you.

…thanks heaps , Harry !

you’re a CHAMPION , mate !


You can use Aluminum too.  We cast on aluminum mold bars for the front edges of counter tops with PE gelcoat resin.  Need to wax once and good to go… aluminum can do intricate shapes steel is just too hard and costly to do.  Be careful not to scratch or dent it… can be sanded to shine.  We use a product called PMR as a semi permanent parting film… I also have a spray can of Chemlease 66 they use for molding urethanes and concrete that works well too.

We need to see the finish product !

Listen to ghettorat.  Wax is the key.  Don’t skip, skimp, or look for alternatives for this part.  

You can make complex molds from fiberglass, or any non-porous material… as long as you DON’T SKIP the wax.  Mold release is the best.  If you can’t easily get that, use car wax.  Rub it on, rub it off, repeat 10 times.  You’re golden.

  What's wrong with dark green releasing agent?  It actually works, and lotsa big manufacturers use it.

+1 on the not skimping…the more similar the two surfaces ie. Fiberglass from a fiberglass mold the more layers of wax needed. Something to mention…you can’t just wipe on and off…you have to wipe on…let haze…wipe off gently…then wait a while for the thin layer to dry rock hard (you cant see it). I have seen my father wax something upwards of 30 times in order to get enough layering for a mold. I have also seen poorly kicked resin eat through wax and stick if it took too long.