PETG Blistering

[ASAP_Gooby]

Hey guys, today I started doing my first bend and when I was finishing up I noticed some air pockets. I hoped this was just space where the bending-hardline-tubing insert and tube weren't touching; but alas, my first bend ended up having a bit of blistering:

 

It's not terrible blistering, but it annoys my that this happened. Any suggestions on my other bends? I think this was bending this single angle for about an hour and a half! But that's because I don't know how hot or close I was supposed to have the heat. I started and 120°F and stepped it up to 500°F after ~50 minutes of not much of a bend. 500°F was obviously way better noway that I think about it, but I heated one side for too long. What temperature should I put the gun at?

 

I'm also able to speed up the fan in the heat gun, should I do this? I would like to get bends done in under 30 minutes without the blistering. 

 

Also, should I use gloves to touch the actual tube to bend it? I was just bending the insert and hoping for a 90... yeah I need to do things differently.

[Zyndo]

4 minutes ago, ASAP_Gooby said:

Snip

You should go to youtube and look up some tube bending guides.

 

 

Everyone has slightly different tactics, but this should give you a pretty good idea of what to do and what not to do.

 

[Lurick]

How far away are you holding the tube? I usually just crank my heat gun to high (not sure of the temp), hold it on a side for ~10 seconds maybe 2 inches away from the gun, turn it by 1/4, and repeat until it's back to the start and then I bend.

[ASAP_Gooby]

6 minutes ago, Zyndo said:

snip

 

 

Literally tho, I've watched pretty much all of them

 

4 minutes ago, Lurick said:

How far away are you holding the tube? I usually just crank my heat gun to high (not sure of the temp), hold it on a side for ~10 seconds maybe 2 inches away from the gun, turn it by 1/4, and repeat until it's back to the start and then I bend.

I was holding it pretty close when I first started out, about an inch or so. Then when I cranked up the heat I didn't really lift it up much higher. I like your idea tho

[Zyndo]

15 minutes ago, ASAP_Gooby said:

Literally tho, I've watched pretty much all of them

Alright, well if that is the case then my recommendations would be to do much of what @Lurick said. don't hold it right up to the gun, heat it slowly and evenly. rotisserie style. like if you were cooking a hot dog over a fire. if you put it right near the fire or in the fire you're going to burn it and bubble it. if you put it above the fire and slowly rotate, you get a nice evenly cooked delicious dog fer yer buns.

 

and then like JayzTwoCents often says, don't force it. when you go to make your bend it should bend willingly. if you have to force your bend its not warm enough yet, and that can cause damage and poor finishes to your tubing.

[ASAP_Gooby]

I DID IT!

Still took a while, but looks WAAAAY better. Thank you!

@Zyndo @Lurick