wonwinglo
SMF Supporter
- Joined
- Apr 18, 2004
- Messages
- 6,754
- Points
- 113
- First Name
- Barry
Blue foam can be the solution to many problems,if you need a quick plug from which to prepare a glass fibre or other shape then this could be your answer,there are many different ways to tackle the problems of making difficult shapes for our models which we will discuss in detail some other time,but for the present here are a few tips gleaned from using this versatile material-
Main suppliers are builders yards or those dealing with insulation,I have found it in both blue and pink colours but the density looks the same,biggest problem is is the sheer size of the panels,so dont forget to take a bread knife (the best tool for rough cutting large areas) with you to make it more manageable and fit into your car.
Say we are intending to make a fuselage then best way is to prepare card templates for the side view and top view,mark out the side first with a marker pen and if you are lucky enough to own a bandsaw rip out the shape leaving a margin all round,next take a large sanding block and sand up to the line,now mark the top shape of the fuselage and all you need here is a Surform with a new blade fitted which will rip through nicely,having done this start shaping to the cross sections from the plan,if there are any undercuts such as a flying boat hull use a curved Pirmagrit tool which you will find invaluable in your tool kit,keep going until you have the rough shape and then start to finish off with coarse glasspaper moving along to fine,you will be surprised at how good a finish that can be obtained despite the porous nature of the material,now mix up some PVA adhesive 50-50 and apply all over,leave overnight and sand down all over,to get a really noice finish cover with lightweight tissue using the thinnede PVA,apply as many coats as desired depending on the models weight factor.
Now for the interesting bit,with your bandsaw ( or an hacksaw blade) cut either down the middle from the top of the fuselage or consider cutting horizontally along a set datum line,either way this prepares the blue foam 'log' for internal removal of material,aim for a sensible wall thickness depending on your skill level or the models application,a good tool for this is an ordinary domestic spoon with the end cut off,sharpen the end like a chisel and ram this into a file handle,scoop out the foam until you are happy with the result,just feel the weight going down along the way ! some soldering irons have hot wire cutter fittings but beware of noxious fumes as it produces that ever dangerous cyanide when heated,best to work outside as this is messy material and it sticks statically to everything it lands on,convince the wife that your lawn really does need to be a different colour and blue is in this year.
Once the sides have been thinned you can join them with PVA if you think a few formers will not come amiss then press a carpet fitters corner tool into the fuselage at the point you want,then transfer this shape to some balsa and glue into place using T-Pins to hold while the glue dries,another tip is to press a glue gun into use to tack glue these while the main glue dries.
Once the joint is dry,run a strip of bandage along the joint and impregnate with thinned down PVA adhesive,the surface takes enamel,acrylic or even emulsion paint nicely.
If you have not tried using blue foam then why not give it a try ? it can be the answer to many difficult to reproduce shapes.
Main suppliers are builders yards or those dealing with insulation,I have found it in both blue and pink colours but the density looks the same,biggest problem is is the sheer size of the panels,so dont forget to take a bread knife (the best tool for rough cutting large areas) with you to make it more manageable and fit into your car.
Say we are intending to make a fuselage then best way is to prepare card templates for the side view and top view,mark out the side first with a marker pen and if you are lucky enough to own a bandsaw rip out the shape leaving a margin all round,next take a large sanding block and sand up to the line,now mark the top shape of the fuselage and all you need here is a Surform with a new blade fitted which will rip through nicely,having done this start shaping to the cross sections from the plan,if there are any undercuts such as a flying boat hull use a curved Pirmagrit tool which you will find invaluable in your tool kit,keep going until you have the rough shape and then start to finish off with coarse glasspaper moving along to fine,you will be surprised at how good a finish that can be obtained despite the porous nature of the material,now mix up some PVA adhesive 50-50 and apply all over,leave overnight and sand down all over,to get a really noice finish cover with lightweight tissue using the thinnede PVA,apply as many coats as desired depending on the models weight factor.
Now for the interesting bit,with your bandsaw ( or an hacksaw blade) cut either down the middle from the top of the fuselage or consider cutting horizontally along a set datum line,either way this prepares the blue foam 'log' for internal removal of material,aim for a sensible wall thickness depending on your skill level or the models application,a good tool for this is an ordinary domestic spoon with the end cut off,sharpen the end like a chisel and ram this into a file handle,scoop out the foam until you are happy with the result,just feel the weight going down along the way ! some soldering irons have hot wire cutter fittings but beware of noxious fumes as it produces that ever dangerous cyanide when heated,best to work outside as this is messy material and it sticks statically to everything it lands on,convince the wife that your lawn really does need to be a different colour and blue is in this year.
Once the sides have been thinned you can join them with PVA if you think a few formers will not come amiss then press a carpet fitters corner tool into the fuselage at the point you want,then transfer this shape to some balsa and glue into place using T-Pins to hold while the glue dries,another tip is to press a glue gun into use to tack glue these while the main glue dries.
Once the joint is dry,run a strip of bandage along the joint and impregnate with thinned down PVA adhesive,the surface takes enamel,acrylic or even emulsion paint nicely.
If you have not tried using blue foam then why not give it a try ? it can be the answer to many difficult to reproduce shapes.
