Ask Dr. Dave

Ask Dr. Dave

Adhesive and sealant troubleshooting tips from Dr. Dave Dunn.

Question: What is the difference between flow-in bonding and weld-through bonding?

Answer: The “weld-through” process is generally accepted as the most economical and effective bonding procedure these days. Weld bonding is commonly used in the automotive industry, at both the OEM level and in body repair. The technique provides the combined benefits of welded joints and adhesively bonded joints. Adhesives used in this application are usually filled with metallic powders to make them electrically conductive.

The term “flow-in” describes bonding processes in which a joint is welded before an adhesive is allowed to flow into the joint. The “weld-through” process involves applying the adhesive first and then welding through the uncured or fully cured adhesive - a common practice in repair procedures. (It is worth mentioning that “flow-in” is sometimes erroneously used to describe processes in which an adhesive is applied and then welded in the liquid state before it has cured.)

Question: I am a re-manufacturer of diesel fuel-injection parts. I am currently experiencing a leakage problem in one of my products, an aluminum casting that contains an aluminum sleeve. I have used epoxy, anaerobic adhesives, flange sealants, press fits and .002” clearance, and yet I still have problems. Can you suggest a remedy?

Answer: It seems to me that you may have an inherent porosity problem with your aluminum castings. Have you considered getting them impregnated with either an anaerobic or heat-cured acrylic sealant prior to applying your adhesive/sealant? These impregnation sealants will fill any porosity in the castings to prevent gas or fluid leaks.


Did you enjoy this article? Click here to subscribe to Adhesives & Sealants Industry Magazine.

Recent Articles by Dave Dunn

You must login or register in order to post a comment.



Image Galleries

ASI April 2014 Photo Gallery

Our April 2014 issue is now available!


ExxonMobil Tackifier Expansion

Dwight Tozer, vice president of ExxonMobil’s Adhesion Industry business, discusses the company’s latest tackifier expansion project with Editor-in-Chief Susan Sutton.

More Podcasts

Adhesives & Sealants Industry Magazine

ASI June 2015 cover

2015 June

Welcome to our annual Dispensing & Curing Equipment Directory!
Table Of Contents Subscribe

"Cultural Fit"

A recent opinion piece in the New York Times observed that new employees are often hired based on the personal similarities they share with their interviewers. How important is “cultural fit” when hiring someone?
View Results Poll Archive


Handbook of Sealant Technology

The Handbook of Sealant Technology provides an in-depth examination of sealants, reviewing their historical developments and fundamentals, adhesion theories and properties, and today’s wide range of applications.

More Products

ASI 2014 Buyers GuideASI's Buyers' Guide

Annual purchasing resource for equipment used in the manufacture/formulation of adhesives, sealants, pressure sensitives, tapes and labels and for application of finished adhesives. 


facebook_40px twitter_40  youtube_40pxlinkedin_40 google+ icon ASI 30px

Clear Seas Research

With access to over one million professionals and more than 60 industry-specific publications, Clear Seas Research offers relevant insights from those who know your industry best. Let us customize a market research solution that exceeds your marketing goals.