Jump to content
Sign in to follow this  
oipigface

Foam Cutting

Recommended Posts

oipigface

In the past, I've always used knives or saws to cut foam, and I thought I would build a hot wire instead. My plan was put off track by finding a cheap one ready built, and complete with a table and fence for not a lot of money on ebay. Included in the kit were three plastic bags, each containing three cutting wires of different weights. These are labelled with the swg rating and the temperature that they reach. (Presumably this is specific to the power supply included in the kit.) Being new to this sort of thing, I was wondering why. Is it to handle different types of foam, different thicknesses, or what?

Share this post


Link to post
Share on other sites
CTR

Not knowing the swg sizes or the PSU, the basics are that the thinner the wire (higher swg) the higher the resistance so the lower the watts with a given PSU.

The ideal is that the wire doesn't touch the foam but the temperature of the wire is such that the radiated heat melts the foam before the wire reaches it.

The higher the temp' of the wire, the quicker you can move through the foam but the wider the slot cut by the melt-back of the foam. Generally, the higher the density of the foam, the hotter the wire needs to be; but different chemical makeups of foam also affect the cut speed/melt speed.

Good luck and practice are the keys to success!

Share this post


Link to post
Share on other sites
Darren_O

We definitely need a link to this cutter :) Fancy having a bash myself at some point.

Share this post


Link to post
Share on other sites
oipigface

Hi Darren, 

     There's good news and bad news.

     BAD: The 'special' price that I paid (£25 if I remember correctly) is no longer available. The current price is £35. 

     GOOD: That includes a circle cutting jig.

     The kit includes 10 wires, power supply and a well-thought-out table complete with fence. 

      I have completed my first project with it, which was building an extension to the box my Cularis came in so that the wing tips would fit in it. The only setup required was to fit the cutter frame onto the table. There's a fitting on the bottom of the table with a couple of butterfly nuts that hold it in position. These allow it to be mounted at angles other than 90degrees, should they be required. The fence also has to be fitted to the table. It has a couple of plastic disks with more butterfly nuts. The disks can be put in any two of three holes, so the fence can be set up parallel to either side of the table, or at an angle. So straight cuts can be angled in any dimension. I don't know how the circular jig works, but I remember cutting loads of circular pieces with holes in the middle for the fuselage of my late-lamented Avro747a. I used a ply template and a knife to cut up some pieces of Baudis packing foam, which then needed a lot of finishing. Whether it is possible with this kit to cut a circular piece with an accurately centred hole, I don't know, but it would save an awful lot of bother if it does. 

         I think I might buy a jig and find out!

https://www.ebay.co.uk/itm/HOT-WIRE-CUTTER-FOR-MODEL-MAKING-CRAFTS-DEPRON-EPP-POLYSTYRENE-NEW/132589791450

Edited by oipigface
Edited to display correct link

Share this post


Link to post
Share on other sites
oipigface

My last reply to Darren was all screwy, because I got the wrong seller on ebay. I've now corrected the link, so it shows the one I actually bought, which cost £29.99, and isn't available with a jig for cutting circles. Apologies to all, especially the sellers involved.

  • Like 1

Share this post


Link to post
Share on other sites
Bobbyr

Not sure if this will help anyone ,

                                   but I thought it was quite interesting , and informative :)

 

                                                                 

 

                            Happy New Year

                                                             Bob

  • Like 1

Share this post


Link to post
Share on other sites
pete beadle

Hi all

Very informative and useful

From personal experience I can confirm that foam cutting is much improved when done by TWO people

Two sets of hands to move the foam around smoothly keeping the cut consistent, and two sets of eyes to check that nothing is missed in preparation or during cutting:)

Particularly important if you're cutting things like foam wing cores is to mark "waypoints" on either side of the foam block being cut to minimise the chance of producing ridges in the core by not keeping every move smooth, and consistently hitting both waypoints at the same time....... 

Most important of all is PRACTICE  before you start cutting cores that you intend to use :yes:

Good luck

Pete

BARCS1702

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.