Hotwire Cutter Power Source/Supply

General Discussion
101

".....I spent over 8 weeks trying to find all the information I needed on the internet to build a hotwire foam cutter...."

 Funny Stuff! I looked at the photo Airframe posted one day and built a hot wire cutter. It took me one afternoon. I've cut at least 25 surfboards.....Variac.....by week 2 we had over ten boards cut. No ohms, no temp ,no watts , no worries.

You win.

 

 

102

 

[quote="$1"]

 Funny Stuff! I looked at the photo Airframe posted one day and built a hot wire cutter. It took me one afternoon. I've cut at least 25 surfboards.....Variac.....by week 2 we had over ten boards cut. No ohms, no temp ,no watts , no worries.

You win.

[/quote]

 

No win or lose.  Better still, everybody wins.  

I like to understand what I am making before I build it, especially when electricity is involved.  I will not be cutting foam until the weather warms up – got nowhere to glass inside.  I would not have considered any of this if Ken at Segway had not suggested using EPS and a hotwire, and somebody here had not posted about using a battery charger anyway.

Seemed like there was too much guesswork going on out here in cyberspace.  So I decided to see what I could learn.  I view more information as a good thing.  The equations are basic and the algebra is simple.  Fixed output power sources can work just fine with the right gauge and length of Nichrome wire and sufficient volts/amps.

Seems like anybody can win.

103

Stingray I’m with you and MD on this one. It’s so easy it not even an issue?

As NIKE say’s in there ads “Just Do It!”

104

Don’t learn something Mr. BgSurfer.  You will disrupt the status quo.

Why use equipment you have when you can buy something?

Use a variac if you want to be cool – all of the real blank makers do.

105
  1. Do not argue with an idiot. He will drag you down to his level and
    beat you with experience. 2. Going to church doesn’t make you a Christian any more than standing
    in
    a garage makes you a car. 3. The last thing I want to do is hurt you.
    But it’s still on the list. 4. If I agreed with you we’d both be
    wrong. 5. We never really grow up, we only learn how to act in
    public. 6. War does not determine who is right - only who is left. 7.
    Knowledge is knowing a tomato is a fruit; Wisdom is not putting it in
    a fruit salad. 8. Evening news is where they begin with ‘Good evening’, and then
    proceed to tell you why it isn’t. 9. A bus station is where a bus stops. A train station is where a train
    stops.  On my desk, I have a work station. 10. How is it one careless match can start a forest fire, but it takes a
    whole box to start a campfire? 11. Dolphins are so smart that within a few weeks of captivity, they can
    train
    people to stand on the very edge of the pool and throw them fish. 12. I
    thought I wanted a career, turns out I just wanted pay checks. 13.
    Whenever I fill out an application, in the part that says “In an
    emergency,
    notify:” I put “Doctor”. 14. I didn’t say it was your fault, I said I
    was blaming you. 15. Behind every successful man is his woman. Behind
    the fall of a
    successful man is usually another woman. 16. You do not need a parachute to skydive. You only need a parachute to
    skydive twice. 17. The voices in my head may not be real, but they have some good
    ideas! 18. Hospitality: Making your guests feel like they’re at home, even if
    you wish they were. 19. I discovered I scream the same way whether I’m about to be devoured
    by
    a great white shark or if a piece of seaweed touches my foot. 20.
    There’s a fine line between cuddling and holding someone down so
    they can’t get away. 21. I always take life with a grain of salt, plus a slice of lemon, and
    a shot of tequila. 22. When tempted to fight fire with fire, remember that the Fire
    Department
    usually uses water. 23. You’re never too old to learn something
    stupid. 24. To be sure of hitting the target, shoot first and call
    whatever you
    hit the target.
    Cheers
    Mooneemick
106

I started this thread to gain knowledge about fixed output hotwire power sources.

I posted the information I learned to help those wanting to use a fixed output power source to make a hotwire cutter.

I have condensed the information presented in this thread and posted it with updates at this link:

http://bgboard.blogspot.com/2011/01/i-spent-over-8-weeks-trying-to-find-all.html

I also summarized some basic information I discussed elsewhere at Sways about Polystyrene (XPS, EPS) foam types/specifications at this link:

http://bgboard.blogspot.com/2013/12/…types-and.html

Maybe some will find these links useful.

 

107

How many of you have had problems with the wire breaking? I’ve tried a variety of wire gauges and power settings. Seems like the wire would get too hot between the foam and the bow and then break.

I’ve had the best results with store bought (online) equipment, but I’ve burned out power supplies from cutting too much foam. The last time I used the hot wire I had a fairly thick wire and a Variac, and that didn’t break. Seemed like I had the best results with 2 people holding the bow.

I have saved several computer power supplies, and I have an assortment of small DC power supplies for the store bought cutters. I bought wire based on what the online companies sell, but from ebay. I think DC is better for the hot wire, but that’s just my experience.

108

I like this/these DIY plans for building  a “low-voltage” variable-output hotwire power supply at the links below.  It allows control over wire temperatures, with a much lower maximum voltage output than a variac.  I want to build and try this.

http://www.jacobs-online.biz/power_supply_design.htm

http://hotwirefoamcutterinfo.com/_DIYPSDesign.html

 

 

109

My company recently moved to a new office. And my boss found some old lab power supplies.

He asked if someone would like to have one.

So now I have a 300W lab power supply similar to the one in the following pic.

 

You can regulate the current. Which means that you calibrate it once to your wire type and can use the same settings for all different wire lengths as long as the same wire type is used.

This thing is without doubt the best hot wire supply ever!

110

Good for you Hans! I am glad that you got to score something surf-related to go with your hard work on the finFoil software.

111

Nice score Hans.  The one in the picture looks like a 30v 3A unit.  I am assuming since yours is 300w it is a 30v 10A unit.

What gauge nichrome wire are you using with it?

112

I have a 30V 10A unit indeed.

It is a different brand than the picture, I just wanted to include a picture of a similar PSU as an illustration.

Not sure about the gauge I’m using. I ordered my wire a long time ago and ordered the correct resistance to work for 60cm wire at 12V. (I used an old computer PSU back then)

113

Check swap meets for old Lionel Model Train transformers.    I have it on good authority that they work extreamly well, in a ‘‘hot wire’’ application.

114

With 0-10A and 0-30v ranges, you can use/choose a nice range of cutter wire gauges.  I like that option.  It would be nice if I could fall into find like yours.  I will be on the lookout for a good deal on a 30v 10A lab power supply.  Again, very nice score.

Using the simple DIY plans at the links I posted before, it looks like a slide dimmer switch with the 12v 8A transformer available from Jacobs Online ($30)** **should allow a decent range of cutter wire gauge choices at a very affordable price.

115

haaaaaa’'stonebrain   start a thread under b g surfer  then troll it  very funy

a merry christmas to ya’’  anyway

 

 

  cheers huie

116

Thanks Hewie.

It must be Christmas Eve in Oz by now.

Merry Christmas to you as well.