foam cutting hot knife
05-06-2003, 09:52 PM
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foam cutting hot knife
hi guys...have just finnished my first foam cutting power supply from the excellent theads in this fourm.....now i want a hot knife for cutting holes and the like......know about the soldering iron....has anyone made there own knife with say 1/16 wire blade...would like to make my own to save money and is hard to sause such iteams down here in New Zealand....thanks
05-07-2003, 01:05 AM
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foam cutting hot knife
05-07-2003, 09:07 PM
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Thanks Jaymom it was your threads that I built the my foam cutter off........I have already made a jigsaw like that for cutting blocks into wing size........What im arfter is to be able to cutt holes into wing cores for lighting or servos....my soldering iron is to harsh and have tryed mounting 1/16 wire on this but the heat disapates through the wire...not enough haet to cut foam.....thanks for the info ....Crewe.
05-12-2003, 09:08 PM
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foam cutting hot knife
Jaymom
Thank you for the info on foam cutting. It it just what I was looking for.
I have an old train transformer and the rest in my junk room. I will put it together an let you know.
Thank you for the info on foam cutting. It it just what I was looking for.
I have an old train transformer and the rest in my junk room. I will put it together an let you know.
05-15-2003, 04:18 AM
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foam cutting hot knife
Glidaguy,
You could try a soldering GUN. Use thick gauge copper wire (thick because it can retain a shape as you pull it through the foam). Somehow, you should shape a lip on the wire so it can rest on a ledge so you can control the depth of the cut.
I've found the best results with a Dremel or other rotary tool and a 5/16" cutting bit. Used in a router attachment, it gives adjustable clean and accurate cuts.
If you have any questions, I'll post some pix.
You could try a soldering GUN. Use thick gauge copper wire (thick because it can retain a shape as you pull it through the foam). Somehow, you should shape a lip on the wire so it can rest on a ledge so you can control the depth of the cut.
I've found the best results with a Dremel or other rotary tool and a 5/16" cutting bit. Used in a router attachment, it gives adjustable clean and accurate cuts.
If you have any questions, I'll post some pix.
05-15-2003, 11:10 PM
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thanks Pattern...forgot about my dremel.......will give it ago.....will have to see if I can beg steel or borrow a trigger soldering iron..
05-17-2003, 06:53 PM
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Sorry guys,
It took a little longer than I expected. Anyway, Here's my setup.
On the right is my dremel mounted on the router attachment. I've constructed my own base plate (it's square as opposed to the round one they supplied). BTW If I were to do it again, I'd make the base plate out of clear plexiglass- that way I can see what I'm doing.
Of the two bits shown, the short one is the High Speed cutter 5/16" (DRE 115). The long one is just an ordinary Zip bit for a Roto-Zip tool. I don't know if you use these tools in NZ. They've become popular here in the states more recently and are very useful cutting drywall. It looks like a drill bit, but it cuts sideways.
The 5/16" bit produces very nice floors, but you can't cut very deep with it. The Zip bit goes deeper, but the walls are a little rougher.
On the left is a template I use for cutting out servo boxes in wings. The white wood along the edges serve as a straightedge so I get clean edges for the walls. I shim up one edge of the template and tape it to the wing so that it lays flat on the wing allowing me to make a pretty accurate box. It usually takes me 3-4 passes each getting progressively deeper (using the 5/16" bit).
To make the template:
1 Determine the desired size of the box
2 Determine the placement of the straightedges (taking into account the length and width of the base plate, and the size of the bit)
3 Glue straightedges onto the template (1/4" ply?).
4 Using the desired bit, make a cutout in the bottom of the template using the straightedges as a guide. As long as you always use the same bit, and use the same orientation of the base plate to the template, it will cut out the foam to the exact shape and location of the template cutout.
It took a little longer than I expected. Anyway, Here's my setup.
On the right is my dremel mounted on the router attachment. I've constructed my own base plate (it's square as opposed to the round one they supplied). BTW If I were to do it again, I'd make the base plate out of clear plexiglass- that way I can see what I'm doing.
Of the two bits shown, the short one is the High Speed cutter 5/16" (DRE 115). The long one is just an ordinary Zip bit for a Roto-Zip tool. I don't know if you use these tools in NZ. They've become popular here in the states more recently and are very useful cutting drywall. It looks like a drill bit, but it cuts sideways.
The 5/16" bit produces very nice floors, but you can't cut very deep with it. The Zip bit goes deeper, but the walls are a little rougher.
On the left is a template I use for cutting out servo boxes in wings. The white wood along the edges serve as a straightedge so I get clean edges for the walls. I shim up one edge of the template and tape it to the wing so that it lays flat on the wing allowing me to make a pretty accurate box. It usually takes me 3-4 passes each getting progressively deeper (using the 5/16" bit).
To make the template:
1 Determine the desired size of the box
2 Determine the placement of the straightedges (taking into account the length and width of the base plate, and the size of the bit)
3 Glue straightedges onto the template (1/4" ply?).
4 Using the desired bit, make a cutout in the bottom of the template using the straightedges as a guide. As long as you always use the same bit, and use the same orientation of the base plate to the template, it will cut out the foam to the exact shape and location of the template cutout.
05-17-2003, 07:09 PM
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Here's a picture of the template in use.
As you can see, I've made marks along the straightedges to ensure I have the correct orientation of the base plate to the template.
Although the bit isn't deep enough to make a cut, you can see that it aligns to the template cutout.
You would then slide the dremel/router base around the template making a box.
As you can see, I've made marks along the straightedges to ensure I have the correct orientation of the base plate to the template.
Although the bit isn't deep enough to make a cut, you can see that it aligns to the template cutout.
You would then slide the dremel/router base around the template making a box.
05-17-2003, 07:30 PM
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Here's a picture of another jig I've used.
This is for cutting vertical holes in foam. I use 1/2" OD brass tube with the edges sharpened.
The wing is sitting in its shucks on the table, and the jig ensures that the tube will cut the hole perpendicular to the table.
Actually, the picture was taken after the fact since the wing joint is already fiberglassed (I haven't tried to cut a hole through fiberglass so I don't know if it would work well).
The hole was bored through the wing to accept 1/2" hardwood dowel, which was used for the wing bolts.
This is for cutting vertical holes in foam. I use 1/2" OD brass tube with the edges sharpened.
The wing is sitting in its shucks on the table, and the jig ensures that the tube will cut the hole perpendicular to the table.
Actually, the picture was taken after the fact since the wing joint is already fiberglassed (I haven't tried to cut a hole through fiberglass so I don't know if it would work well).
The hole was bored through the wing to accept 1/2" hardwood dowel, which was used for the wing bolts.
05-17-2003, 07:58 PM
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Last picture I promise!
Here's what I use for servo wires.
This is also a 1/2" OD brass tube with the edges sharpened. Actually the jig runs the length of the wing and then some. On the other side are vertical pieces of wood just like these. On the vertical pieces is a mark which lines up with the path of the brass tube making it easier to position the wing exactly.
Twist the brass tube while pushing in gently. When it doesn't seem like it's cutting any more, remove the tube and remove the foam from inside the tube.
Now... don't tell my wife I've been making all these jigs. She's liable to think I have too much time on my hands, then I'll have to start mowing the lawn again.
This is also a 1/2" OD brass tube with the edges sharpened. Actually the jig runs the length of the wing and then some. On the other side are vertical pieces of wood just like these. On the vertical pieces is a mark which lines up with the path of the brass tube making it easier to position the wing exactly.
Twist the brass tube while pushing in gently. When it doesn't seem like it's cutting any more, remove the tube and remove the foam from inside the tube.
Now... don't tell my wife I've been making all these jigs. She's liable to think I have too much time on my hands, then I'll have to start mowing the lawn again.
05-17-2003, 08:12 PM
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foam cutting hot knife
Seems to me that I remember some guy a few months back posting pix of his aileron installation in a foam wing. You may want to search for that thread.
Very slick, very professional.
Very slick, very professional.
