Jump to content

PVC Karrimor-style Frame Build


mikelbrierly
 Share

Recommended Posts

Hey guys, I wanted to share my experience building my own pack frame. I partially wanted to save some money, but it also just seemed like a fun challenge. I initially thought about getting an aluminum pipe bender and doing it with aluminum, but I figured that would be a huge headache, so I went with PVC. The primary issue with heat gunning/bending pvc is that it kinks really easily, so I did some research online of different methods, and I came across some unique solutions that I use here -

 

First I gathered as many dimensions as I could of the frame. It seems like there’s a couple variations of the Karrimor brand out there, but I feel like the trapezoid style with the single top bar is the closest (from what I’ve seen). Juan posted a great photo of his frame with a load of dimensions, so that was my starting point. I also used Airborne troopers build as a reference for curves and placement of trays which was really helpful. 

 

NOTE: I have the Trooperbay pack starter kit, and I believe some of the dimensions are off by a bit, specifically on the seed trays, but it’s what I have, so I fudged a couple measurements to work better with the trays that I have. 

 

Materials:

1/2” PVC piping (it says 1/2”, but the real diameter is 3/4”)

Sand (I used a bag of play sand)

Masking tape

Heat gun

An old pot

Oven mitt

Thick gloves

Small funnel

Wooden dowel slightly smaller than the interior of the PVC

 

First I drew out a template of the trapezoid shape (the bottom of the frame) that I could follow to bend the pipe to shape.

28119472507_412bf0403c_z_d.jpg

 

Next I marked the halfway point on the pipe, and the first two bends. 

28119465827_3722e62fe8_z_d.jpg

 

Then I masked off one end of the pipe and filled it to the brim with sand using the small funnel

42987642331_5066301b2a_z_d.jpg

 

Once  the amount of sand had been measured out, I dumped it into a pot and put it on the stove on high heat for about 5 - 10 minutes. You basically just want it as hot as possible.

42987641681_53134546cb_z_d.jpg

28119471907_b6c9747080_z_d.jpg

 

At this point I was ready to pour it back in the pipe and tape the other end off with masking tape. I made sure I had my thick gloves on and oven mitt close by, and also made sure I had the template all ready to go. Here’s a gif of how soft the pipe gets just a minute or so after pouring the sand in and taping it off.

42269626944_5240032845_o_d.gif

 

Now I was able to lay the pipe on the template and slowly bend it to match the form I had drawn out. I used a heat gun a little bit for the corners, but I’m not sure it was even necessary. The hot sand acted as more than just the heating element, it also prevented the pipe from kinking and collapsing in on itself.

28119471517_a26bddebd7_z_d.jpg

 

I waited for the PVC to cool to hold the shape, then used a heat gun to bend the 45 degree angles, using the floor and wall to prop it up while it cooled.

42987638881_ef604631ec_z_d.jpg

 

The next thing I needed to do was to give the long vertical pipes a subtle bend backwards. I sketched out what I felt like the curve should be, and then re-heated the sand for one side at a time. The sand is much more effective for soft subtle curves than a heat gun. (I also used a bojangles setup to prop everything up for a while to cool)

41177696850_57fe9cbd1c_z_d.jpg

 

I repeated the process on the other side...

28119470867_13023179d8_z_d.jpg

 

And also used the heated sand technique to bend the crossbar with a gentle curve. I cut it a couple inches longer than I’d need.

41177696020_715bf099b2_z_d.jpg

28119470377_a6200f37e1_z_d.jpg

 

To attach the crossbar, I cut it down to the distance between the crossbars plus about an inch. Then I wrapped a piece of PVC with sandpaper to sand down the ends of the crossbar so it would fit nicely in place.

42938127972_35e1c0afe5_z_d.jpg

 

To attach the crossbar, I decided to use a couple wooden plugs (I made by whittling down the shape from a dowel) with pilot holes drilled in them that can be screwed in from the outside. 

42938127442_18e9a2ddc0_z_d.jpg

 

Then I hammered them into the ends of the crossbar to be flush with the shallowest point.

28119468477_c6b6d57884_z_d.jpg

 

After drilling pilot holes in the frame, I screwed into the crossbar wood plugs to fasten it in place.

41177693490_bebe4438fb_z_d.jpg

 

Once that was in place, I cut the ends off the frame to about 3” above the crossbar, and voila!

28119464357_b6ea3d6d2f_z_d.jpg

 

After a coat of paint and some old backpack straps, I’ll have a Karrimor-esque frame for about $10.

I hope that this might help some people build their own affordable pack frame!

  • Upvote 3
Link to comment
Share on other sites

Hey guys, I wanted to share my experience building my own pack frame. I partially wanted to save some money, but it also just seemed like a fun challenge. I initially thought about getting an aluminum pipe bender and doing it with aluminum, but I figured that would be a huge headache, so I went with PVC. The primary issue with heat gunning/bending pvc is that it kinks really easily, so I did some research online of different methods, and I came across some unique solutions that I use here -
 
First I gathered as many dimensions as I could of the frame. It seems like there’s a couple variations of the Karrimor brand out there, but I feel like the trapezoid style with the single top bar is the closest (from what I’ve seen). Juan posted a great photo of his frame with a load of dimensions, so that was my starting point. I also used Airborne troopers build as a reference for curves and placement of trays which was really helpful. 
 
NOTE: I have the Trooperbay pack starter kit, and I believe some of the dimensions are off by a bit, specifically on the seed trays, but it’s what I have, so I fudged a couple measurements to work better with the trays that I have. 
 
Materials:
1/2” PVC piping (it says 1/2”, but the real diameter is 3/4”)
Sand (I used a bag of play sand)
Masking tape
Heat gun
An old pot
Oven mitt
Thick gloves
Small funnel
Wooden dowel slightly smaller than the interior of the PVC
 
First I drew out a template of the trapezoid shape (the bottom of the frame) that I could follow to bend the pipe to shape.
28119472507_412bf0403c_z_d.jpg
 
Next I marked the halfway point on the pipe, and the first two bends. 
28119465827_3722e62fe8_z_d.jpg
 
Then I masked off one end of the pipe and filled it to the brim with sand using the small funnel
42987642331_5066301b2a_z_d.jpg
 
Once  the amount of sand had been measured out, I dumped it into a pot and put it on the stove on high heat for about 5 - 10 minutes. You basically just want it as hot as possible.
42987641681_53134546cb_z_d.jpg
28119471907_b6c9747080_z_d.jpg
 
At this point I was ready to pour it back in the pipe and tape the other end off with masking tape. I made sure I had my thick gloves on and oven mitt close by, and also made sure I had the template all ready to go. Here’s a gif of how soft the pipe gets just a minute or so after pouring the sand in and taping it off.
42269626944_5240032845_o_d.gif
 
Now I was able to lay the pipe on the template and slowly bend it to match the form I had drawn out. I used a heat gun a little bit for the corners, but I’m not sure it was even necessary. The hot sand acted as more than just the heating element, it also prevented the pipe from kinking and collapsing in on itself.
28119471517_a26bddebd7_z_d.jpg
 
I waited for the PVC to cool to hold the shape, then used a heat gun to bend the 45 degree angles, using the floor and wall to prop it up while it cooled.
42987638881_ef604631ec_z_d.jpg
 
The next thing I needed to do was to give the long vertical pipes a subtle bend backwards. I sketched out what I felt like the curve should be, and then re-heated the sand for one side at a time. The sand is much more effective for soft subtle curves than a heat gun. (I also used a bojangles setup to prop everything up for a while to cool)
41177696850_57fe9cbd1c_z_d.jpg
 
I repeated the process on the other side...
28119470867_13023179d8_z_d.jpg
 
And also used the heated sand technique to bend the crossbar with a gentle curve. I cut it a couple inches longer than I’d need.
41177696020_715bf099b2_z_d.jpg
28119470377_a6200f37e1_z_d.jpg
 
To attach the crossbar, I cut it down to the distance between the crossbars plus about an inch. Then I wrapped a piece of PVC with sandpaper to sand down the ends of the crossbar so it would fit nicely in place.
42938127972_35e1c0afe5_z_d.jpg
 
To attach the crossbar, I decided to use a couple wooden plugs (I made by whittling down the shape from a dowel) with pilot holes drilled in them that can be screwed in from the outside. 
42938127442_18e9a2ddc0_z_d.jpg
 
Then I hammered them into the ends of the crossbar to be flush with the shallowest point.
28119468477_c6b6d57884_z_d.jpg
 
After drilling pilot holes in the frame, I screwed into the crossbar wood plugs to fasten it in place.
41177693490_bebe4438fb_z_d.jpg
 
Once that was in place, I cut the ends off the frame to about 3” above the crossbar, and voila!
28119464357_b6ea3d6d2f_z_d.jpg
 
After a coat of paint and some old backpack straps, I’ll have a Karrimor-esque frame for about $10.
I hope that this might help some people build their own affordable pack frame!


That turned out really nice.


Sent from my iPhone using Tapatalk
Link to comment
Share on other sites

That is awesome! It looks great and helps with the cost. Those real frames are getting harder and harder to find and more expensive.
I've been working on up grading my pack and have gone through a few aluminum pipes trying to do the same with hot sand.
Hasn't worked that well for me. I'll definitely give this technique a try. Thanks!

Sent from my SM-G930W8 using Tapatalk

  • Like 1
Link to comment
Share on other sites

Wow, what a great way to heat up the PVC and avoid kinks!

Thanks for sharing your experiment and thoroughly documenting the process with so many photos. The end product looks fantastic!

Charlie

Link to comment
Share on other sites

1 hour ago, Airborne Trooper said:

I like this method as opposed to all the PVC joints. Great work! 

Advantage is that this makes it more structurally sound too, my first pvc frame fell apart once, that was super fun lol. 

Link to comment
Share on other sites

Thanks everyone! I was thinking it’d be cool to maybe build some kind of template to make a bunch of these if enough people would be interested. Kind of like this but for the whole frame - 3df0434d1dabba56a4c8590fedf0b1ef.jpeg


Sent from my iPhone using Tapatalk

Link to comment
Share on other sites

  • 2 weeks later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  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.

 Share

×
×
  • Create New...