Sealing balsa

[nevinsParticipant @nevins]

So then time to share your wisdom guys. After sitting in the workshop fora few hours trying to get a smooth finish on a hull Its getting the better of me.

 

I’m attempting to use sanding sealer on the hull and after around 8 coats of the stuff the hull still looks terrible. The method I amusing is as follows.

 

– 2 coats of sealer.

– 800 g paper

– 2 coats of sealer

– another dose of 800g

– 2 coats of sealer

– 1000g

– 1coat of sealer

– 1200g and then a light 1500g.

 

After all this as a trial I sprayed on some primer; yes you guessed it. The balsa grain is still showing through.

Any advice would be welcome.

Gareth 

[nevinsParticipant @nevins]

[Colin BishopModerator @colinbishop34627]

It will work eventually Gareth but can take a long time. I think most people these days would sheath a balsa hull using tissue and finishing resin. It makes it tougher too.

 

Usually GRP tissue is used but this is quite hard to rub down (being glass!). I have successfully used nappy liners which look just like GRP but are of course softer and do a good job of reinforcing the resin. (Unused ones are best…)

 

Great to see somebody actually constructing their own hull.

 

Colin

[nevinsParticipant @nevins]

Thanks for the information, I did an experiment with a hull I had lying around before and coated in in Fg Tissue, but found that the hull distorted slightly, but that may have been down to the ration used as it did get quite hot.( new style resin and had to have a play lol)

 

As for making my own hulls, I find it a key part to modelling. My father taught me how to build boats when I was young and have done it ever since. Although I have only really started using balsa recently, as I always used ply before now.

gareth 

[Ian GardnerParticipant @iangardner62867]

How about a light filler spread on and sanded down- you can get model fillers, I’ve just bought some stuff made by DeLuxe called Model Lite- I think it must have gold dust in it!! I haven’t tried it yet though. I used to use Polyfilla Fine Spackle but I think epoxy is the way to go in future. Z Poxy make a nice finishing epoxy which goes on well and sets fairly quickly.

 

Whisper this- I think we can get a bit hung up about fine finish- I’ve spent ages rubbing down and repainting only to prang the boat (or  worse, have it pranged) after a few outings.

But of course, each to his own.

 

Have fun!

Ian

[nevinsParticipant @nevins]

Thanks for the suggestions Ian, I have a few old hulls here so will be trying out all methods.

[Carsten PaulsenParticipant @carstenpaulsen54581]

Hello there

 

Due to my job situation I have stared to build some of the designs from plans the magazine (as I have the time for it) I just finalized the skimmer (Glynn Guest design) I start up with 2 coats of Glittfix from Graupner with a rubdown between with 400g paper ( it can be replaced with talcum / baby-powder mixed with dope). Any deep defects gets some light sander filler for wood and a rub down with 400g paper. Then I coat it with tissue and dope like a model plane. It gets a rub down with 400g paper and 2 more coats of 50/50 dope and thinner with a rub down 400-600g paper in between and in the end with 600-800g paper.

Then a spray of sander for cars and a rubdown with 800-1000g paper a layer more if it’s needed. Then a primer rub down with 1200g and the the topcoat 2-3 layers with at light rub down in between. In the end it gets some layers of clear coat to seal the surface.

 

But hey what is the purpose of the model, to be a display 110% nice and perfect or is it for fun at the pond ? (I forgot to seal the internals of the Skimmer and it doesn’t have that perfect figure any more after a spray of water)

 

Br

Carsten

Denmark

 

 

[nevinsParticipant @nevins]

Its for on the pond but im a bit ocd when it comes to finishing lol.

[Carsten PaulsenParticipant @carstenpaulsen54581]

I can recall that “problem” but sometimes you have to snap out of it (said by the same person that just spend some 40 hours polishing back the colour on a RED Citroen ZX from 94 worth around 500&#163

 

Keep on the work

 

Br

C

[Tony HadleyParticipant @tonyhadley]

Gareth

 

One method I have used with success is to obtain a pair of fine denier ladies tights. Cut off one leg, cut off the foot and push the hull through. Paint or varnish one coat and allow to dry. sand off at deck level. The hull can then be finished with paint and varnish until the weave disappears. Lightly sand and finish as with any other wood.

 

The only drawback with this method is when the model has a deep keep. In this case it is best to fix an obeche keel externally, after the hull has been finished, as above.

 

Tony.

[Dave MilbournParticipant @davemilbourn48782]

The most frequent error made with sanding sealer is to use it too thick. I always thin it down to the consistency of milk and slap on several coats which just sink into the wood and set up. I then use lightweight modelling tissue and more sealer to build up to a nice finish for the primer and top coats (see the piccies of my little Swordsman on my album pages).

If you would like a copy of an article on this very subject (which accompanied a plan I did for MB about a million years ago) then please PM me your regular E-Mail address and I’ll cheerfully send it over. It’s not the only way but it works for me and for the modellers who’ve used it after reading the article.

Dave M

[Geoff CropperParticipant @geoffcropper73342]

I use Ronseal Woodrot Preserver, It’s diluted GRP resin ,like water, which is made to paint onto woodrot as a temp. repair.       It  soaks deep into the wood then sets hard and easy to sand smooth.        Being a fan of Glynn Guest designs, I use this on all my balsa hulls, coating them inside and out with several coats,sanding smooth then painting.     It really makes the balsa very hard.         Regards,  Geoff.

[ashley needhamParticipant @ashleyneedham69188]

Yes, I tried this on a model and it does seem to work quite well, being designed as it is, to soak into wood and harden it.

 

Ashley

[nevinsParticipant @nevins]

Cheers for the replies, as of late I have not been able to get any modelling done due to working on cars all the time, and supras are a nightmare to work on if the owners have not wax oiled underneath. Can make a simple job like a lower arm into a nightmare involving removal of the whole rear subframe. Will be back on the models soon though.

 

Gareth 

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