How to restore melted ramps from flamepolishing
Article by P. van Leijen. The author of this article (and this website) cannot be held responsible in any way for any damage that occurs of using these instructions. Use at own risk !!
Flame polishing plastic ramps is one skill that is very useful to make a ramp look as good as new again. However as it's a skill, one has to learn it, and there are risks involved.. sometimes flamepolishing goes wrong and results can be terrible. Especially if the plastic ramp involved is pretty expensive or even not available for sale.
I've already flamepolished multiple ramps and use a lot of information, articles on the internet and movies about it. The risk with flamepolishing is that the heat will stay in the plastic after the torch has been removed, so it can still melt or deform if you're not careful.
When I had flamepolished the long Skyway-ramp of my Whirlwind pinball machine, it seems I kept the torch a bit too long on the plastic. In the short bend the plastic had deformed and some bumps have occured. When I was busy it looked ok but after the ramp had cooled down the damage became visible. This can be seen in the picture below.
As a reproduction ramp is quite expensive (especially compared to the total value of this game) and I prefer to try and repair things myself instead of buying everything new, I wanted to figure out a way to repair the damage so the ramp at least became useable again.
After a few days of thinking I knew there had to be a way to melt the plastic again in correct shape, if only I would have a mold for it. My girlfriend had the idea of using artists clay. I tried this, instructions are below.
- Enough space, clean water and soft cotton cloth.
- Artists clay, very fine and self-drying
- Some clear plastic foil
- pictures of how the ramp is supposed to look like as a reference
- Clean the ramp very well
- Select parts in about 5 to 10 cm (2 - 4 inch) you're going to do at a time
- Cover the inside of the ramp with plastic foil, so you can remove the clay easily
- Take a piece of clay, use enough water and make is soft and smooth in about the correct shape
- Push the clay into the ramp (with plastic foil underneath) and push real well so fills the ramp completely and takes over its shape.
- Let this sit and harden for a few minutes, how long depends on the type of clay.
- Careful remove the clay, which can be difficult in bends. Make sure the shape of the clay stays intact.
- If you need to repair multiple parts, repeat the previous steps for each part. Remember very well where each part goes, I put everything on plastic plates that I marked.
- Let the clay parts dry long enough until they're completely hardened (one day or more, check the packing).
Repairing the melted ramp
- Clean the ramp very wel and fit each clay part to check it's a perfect fit. Mark the clay and ramp so you know how they have to fit exactly.
- Now check the melted parts of the ramp and color the clay where it doesn't fit and needs to be adjusted for how the ramp should become.
- Take new parts of clay and fill the marked parts. Use enough water, your hands and other tools to make the repairs very smooth. Make sure you don't make any mistakes, measure things, check pictures of the original ramp, .. just do anything you need to recreate the original shape of the ramp.
- Do this for every clay part you had made.
- Now let the adjusted clay parts dry (again 1 day or more..)
- Again fit each part in the ramp. If they're not perfect enough, repeat the previous steps and add (or remove ?) small parts until they look like the ramp has to be.
Now, final steps. We're going to fix our ramp and give it back its original shape.
Make sure the clay is very clean and smooth
Again clean the ramp very well, double check ramp and clay are clean.. because any loose dirt left will be burnt into the plastic of your ramp and will cannot be removed !
Take a smooth piece of cloth (ie an old tshirt) so you can put pressure on the plastic once its heated.
Heating and fitting the clay molds can be done on 2 ways.
- Careful heat the inside and outside of the ramp using your torch, as if you were flamepolishing. Feel often with your hand if the plastic becomes hot enough. Don't make it too hot (we don't want to burn it and have bubbles !), remember the heat will stay for a while in the plastic. Once the ramp is warm enough, use the clean cloth and push the clay mold in place. Look very careful, feel if there are still parts that need extra pressure. The plastic must be fit against the clay and stay this way. If necessary blow on the plastic to cool it off. Key to success is to take your time for it and don't put too much pressure..
- Another way is to put the piece of clay in the ramp and only heat the plastic from the outside.. Again heat it in short bursts until you feel it becomes soft enough and then push down on the clay.
For both types it's important the heat is introduced gradually. If you heat it too fast the plastic
will burn or airbubbles occur.
Once you've done one clay part, let the ramp cool off long enough (15 minutes or more) before you continue with the next part.
Once everything is done, clean very well and flamepolish again if necessary..
This is how I have repaired my misformed plastic ramp. Maybe there are other techniques, which I'd love to hear about.
Below is the Whirlwind ramp. The game plays very well again !